diff --git a/apm-collector/apm-collector-storage/collector-storage-es-provider/src/main/java/org/apache/skywalking/apm/collector/storage/es/dao/ui/ServiceMetricEsUIDAO.java b/apm-collector/apm-collector-storage/collector-storage-es-provider/src/main/java/org/apache/skywalking/apm/collector/storage/es/dao/ui/ServiceMetricEsUIDAO.java
index cd8cb02f6..e8f6fd81d 100644
--- a/apm-collector/apm-collector-storage/collector-storage-es-provider/src/main/java/org/apache/skywalking/apm/collector/storage/es/dao/ui/ServiceMetricEsUIDAO.java
+++ b/apm-collector/apm-collector-storage/collector-storage-es-provider/src/main/java/org/apache/skywalking/apm/collector/storage/es/dao/ui/ServiceMetricEsUIDAO.java
@@ -162,13 +162,15 @@ public class ServiceMetricEsUIDAO extends EsDAO implements IServiceMetricUIDAO {
 
         BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
         boolQuery.must().add(QueryBuilders.rangeQuery(ServiceMetricTable.COLUMN_TIME_BUCKET).gte(start).lte(end));
-        boolQuery.must().add(QueryBuilders.termQuery(ServiceMetricTable.COLUMN_APPLICATION_ID, applicationId));
+        if (applicationId != 0) {
+            boolQuery.must().add(QueryBuilders.termQuery(ServiceMetricTable.COLUMN_APPLICATION_ID, applicationId));
+        }
         boolQuery.must().add(QueryBuilders.termQuery(ServiceMetricTable.COLUMN_SOURCE_VALUE, metricSource.getValue()));
 
         searchRequestBuilder.setQuery(boolQuery);
         searchRequestBuilder.setSize(0);
 
-        TermsAggregationBuilder aggregationBuilder = AggregationBuilders.terms(ServiceMetricTable.COLUMN_SERVICE_ID).field(ServiceMetricTable.COLUMN_SERVICE_ID).size(100);
+        TermsAggregationBuilder aggregationBuilder = AggregationBuilders.terms(ServiceMetricTable.COLUMN_SERVICE_ID).field(ServiceMetricTable.COLUMN_SERVICE_ID).size(top);
         aggregationBuilder.subAggregation(AggregationBuilders.sum(ServiceMetricTable.COLUMN_TRANSACTION_CALLS).field(ServiceMetricTable.COLUMN_TRANSACTION_CALLS));
         aggregationBuilder.subAggregation(AggregationBuilders.sum(ServiceMetricTable.COLUMN_TRANSACTION_ERROR_CALLS).field(ServiceMetricTable.COLUMN_TRANSACTION_ERROR_CALLS));
         aggregationBuilder.subAggregation(AggregationBuilders.sum(ServiceMetricTable.COLUMN_TRANSACTION_DURATION_SUM).field(ServiceMetricTable.COLUMN_TRANSACTION_DURATION_SUM));
diff --git a/apm-collector/apm-collector-ui/collector-ui-jetty-provider/src/main/java/org/apache/skywalking/apm/collector/ui/query/OverViewLayerQuery.java b/apm-collector/apm-collector-ui/collector-ui-jetty-provider/src/main/java/org/apache/skywalking/apm/collector/ui/query/OverViewLayerQuery.java
index 6d1fa55a9..afbec260d 100644
--- a/apm-collector/apm-collector-ui/collector-ui-jetty-provider/src/main/java/org/apache/skywalking/apm/collector/ui/query/OverViewLayerQuery.java
+++ b/apm-collector/apm-collector-ui/collector-ui-jetty-provider/src/main/java/org/apache/skywalking/apm/collector/ui/query/OverViewLayerQuery.java
@@ -28,7 +28,7 @@ import org.apache.skywalking.apm.collector.storage.ui.overview.AlarmTrend;
 import org.apache.skywalking.apm.collector.storage.ui.overview.ClusterBrief;
 import org.apache.skywalking.apm.collector.storage.ui.overview.ConjecturalAppBrief;
 import org.apache.skywalking.apm.collector.storage.ui.server.AppServerInfo;
-import org.apache.skywalking.apm.collector.storage.ui.service.ServiceInfo;
+import org.apache.skywalking.apm.collector.storage.ui.service.ServiceMetric;
 import org.apache.skywalking.apm.collector.ui.graphql.Query;
 import org.apache.skywalking.apm.collector.ui.service.AlarmService;
 import org.apache.skywalking.apm.collector.ui.service.ApplicationService;
@@ -118,8 +118,10 @@ public class OverViewLayerQuery implements Query {
         return null;
     }
 
-    public List<ServiceInfo> getTopNSlowService(Duration duration, int topN) {
-        return null;
+    public List<ServiceMetric> getTopNSlowService(Duration duration, int topN) throws ParseException {
+        long start = DurationUtils.INSTANCE.exchangeToTimeBucket(duration.getStart());
+        long end = DurationUtils.INSTANCE.exchangeToTimeBucket(duration.getEnd());
+        return getServiceNameService().getSlowService(duration.getStep(), start, end, topN);
     }
 
     public List<AppServerInfo> getTopNServerThroughput(Duration duration, int topN) {
diff --git a/apm-collector/apm-collector-ui/collector-ui-jetty-provider/src/main/java/org/apache/skywalking/apm/collector/ui/service/ServiceNameService.java b/apm-collector/apm-collector-ui/collector-ui-jetty-provider/src/main/java/org/apache/skywalking/apm/collector/ui/service/ServiceNameService.java
index a4de32ea7..2342deb3b 100644
--- a/apm-collector/apm-collector-ui/collector-ui-jetty-provider/src/main/java/org/apache/skywalking/apm/collector/ui/service/ServiceNameService.java
+++ b/apm-collector/apm-collector-ui/collector-ui-jetty-provider/src/main/java/org/apache/skywalking/apm/collector/ui/service/ServiceNameService.java
@@ -20,14 +20,18 @@ package org.apache.skywalking.apm.collector.ui.service;
 
 import java.text.ParseException;
 import java.util.List;
+import org.apache.skywalking.apm.collector.cache.CacheModule;
+import org.apache.skywalking.apm.collector.cache.service.ServiceNameCacheService;
 import org.apache.skywalking.apm.collector.core.module.ModuleManager;
 import org.apache.skywalking.apm.collector.storage.StorageModule;
 import org.apache.skywalking.apm.collector.storage.dao.ui.IServiceMetricUIDAO;
 import org.apache.skywalking.apm.collector.storage.dao.ui.IServiceNameServiceUIDAO;
+import org.apache.skywalking.apm.collector.storage.table.MetricSource;
 import org.apache.skywalking.apm.collector.storage.ui.common.ResponseTimeTrend;
 import org.apache.skywalking.apm.collector.storage.ui.common.SLATrend;
 import org.apache.skywalking.apm.collector.storage.ui.common.Step;
 import org.apache.skywalking.apm.collector.storage.ui.service.ServiceInfo;
+import org.apache.skywalking.apm.collector.storage.ui.service.ServiceMetric;
 import org.apache.skywalking.apm.collector.storage.utils.DurationPoint;
 import org.apache.skywalking.apm.collector.ui.utils.DurationUtils;
 
@@ -38,10 +42,12 @@ public class ServiceNameService {
 
     private final IServiceNameServiceUIDAO serviceNameServiceUIDAO;
     private final IServiceMetricUIDAO serviceMetricUIDAO;
+    private final ServiceNameCacheService serviceNameCacheService;
 
     public ServiceNameService(ModuleManager moduleManager) {
         this.serviceNameServiceUIDAO = moduleManager.find(StorageModule.NAME).getService(IServiceNameServiceUIDAO.class);
         this.serviceMetricUIDAO = moduleManager.find(StorageModule.NAME).getService(IServiceMetricUIDAO.class);
+        this.serviceNameCacheService = moduleManager.find(CacheModule.NAME).getService(ServiceNameCacheService.class);
     }
 
     public int getCount() {
@@ -66,4 +72,15 @@ public class ServiceNameService {
         slaTrend.setTrendList(serviceMetricUIDAO.getServiceSLATrend(serviceId, step, durationPoints));
         return slaTrend;
     }
+
+    public List<ServiceMetric> getSlowService(Step step, long start, long end,
+        Integer top) throws ParseException {
+        List<ServiceMetric> slowServices = serviceMetricUIDAO.getSlowService(0, step, start, end, top, MetricSource.Callee);
+        slowServices.forEach(slowService -> {
+            slowService.setName(serviceNameCacheService.get(slowService.getId()).getServiceName());
+            //TODO
+            slowService.setTps(1);
+        });
+        return slowServices;
+    }
 }
diff --git a/apm-protocol/apm-ui-protocol/src/main/resources/ui-graphql/overview-layer.graphqls b/apm-protocol/apm-ui-protocol/src/main/resources/ui-graphql/overview-layer.graphqls
index 04b1033a6..50e1ff26c 100644
--- a/apm-protocol/apm-ui-protocol/src/main/resources/ui-graphql/overview-layer.graphqls
+++ b/apm-protocol/apm-ui-protocol/src/main/resources/ui-graphql/overview-layer.graphqls
@@ -32,6 +32,6 @@ extend type Query {
     getClusterBrief(duration: Duration!): ClusterBrief
     getAlarmTrend(duration: Duration!): AlarmTrend
     getConjecturalApps(duration: Duration!): ConjecturalAppBrief
-    getTopNSlowService(duration: Duration!, topN: Int!): [ServiceInfo!]!
+    getTopNSlowService(duration: Duration!, topN: Int!): [ServiceMetric!]!
     getTopNServerThroughput(duration: Duration!, topN: Int!): [AppServerInfo!]!
 }