diff --git a/components/statistic/doc/index.en-US.md b/components/statistic/doc/index.en-US.md
index bc2db60116f..1a353050504 100644
--- a/components/statistic/doc/index.en-US.md
+++ b/components/statistic/doc/index.en-US.md
@@ -24,8 +24,8 @@ Display statistic number.
 | `[nzValue]` | Value | `string｜number` | - |
 | `[nzValueStyle]` | Value CSS style | `Object` | - |
 | `[nzValueTemplate]` | Custom template to render a number | `TemplateRef<{ $implicit: NzStatisticValueType }>` | - |
-| `[nzDecimalSeparator]` | Decimal separator | `string` | "." |
-| `[nzGroupSeparator]` | Group separator | `string` | "," |
+| `[nzDecimalSeparator]` | Decimal separator | `string` | `.` |
+| `[nzGroupSeparator]` | Group separator | `string` | `,` |
 
 ### nz-countdown
 
diff --git a/components/statistic/doc/index.zh-CN.md b/components/statistic/doc/index.zh-CN.md
index 0a381fc5ce6..b8d7e8702b5 100644
--- a/components/statistic/doc/index.zh-CN.md
+++ b/components/statistic/doc/index.zh-CN.md
@@ -25,8 +25,8 @@ type: Data Display
 | `[nzValue]` | 数值内容 | `string｜number` | - |
 | `[nzValueStyle]` | 设置数值的样式 | `Object` | - |
 | `[nzValueTemplate]` | 自定义数值展示 | `TemplateRef<{ $implicit: NzStatisticValueType }>` | - |
-| `[nzDecimalSeparator]` | 小数位分隔符 | `string` | "." |
-| `[nzGroupSeparator]` | 千位分隔符 | `string` | "," |
+| `[nzDecimalSeparator]` | 小数位分隔符 | `string` | `.` |
+| `[nzGroupSeparator]` | 千位分隔符 | `string` | `,` |
 
 ### nz-countdown
 
diff --git a/components/statistic/nz-countdown.component.ts b/components/statistic/nz-countdown.component.ts
index 39c9796a012..8b924677299 100644
--- a/components/statistic/nz-countdown.component.ts
+++ b/components/statistic/nz-countdown.component.ts
@@ -2,7 +2,9 @@ import {
   ChangeDetectionStrategy,
   ChangeDetectorRef,
   Component,
-  Input, NgZone, OnChanges,
+  Input,
+  NgZone,
+  OnChanges,
   OnDestroy,
   OnInit, SimpleChanges,
   ViewEncapsulation
@@ -27,10 +29,10 @@ export class NzCountdownComponent extends NzStatisticComponent implements OnInit
   diff: number;
   displayText = '';
   target: number;
-  updater_: Subscription;
+  updater_ = new Subscription();
 
-  constructor(protected cdr: ChangeDetectorRef, private ngZone: NgZone) {
-    super(cdr);
+  constructor(private cdr: ChangeDetectorRef, private ngZone: NgZone) {
+    super();
   }
 
   /** @override */
@@ -62,25 +64,21 @@ export class NzCountdownComponent extends NzStatisticComponent implements OnInit
   startTimer(): void {
     // NOTE: let interval triggered outside of zone for performance considerations.
     this.ngZone.runOutsideAngular(() => {
-      if (!this.updater_) {
-        this.updater_ = interval(REFRESH_INTERVAL).subscribe(() => {
-          this.updateValue();
-          this.cdr.detectChanges();
-        });
-      }
+      this.stopTimer();
+      this.updater_ = interval(REFRESH_INTERVAL).subscribe(() => {
+        this.updateValue();
+        this.cdr.detectChanges();
+      });
     });
   }
 
   stopTimer(): void {
-    if (this.updater_) {
-      this.updater_.unsubscribe();
-      this.updater_ = null;
-    }
+    this.updater_.unsubscribe();
+    this.updater_ = null;
   }
 
   /**
    * Update time that should be displayed on the screen.
-   * @override
    */
   protected updateValue(): void {
     this.diff = Math.max(this.target - Date.now(), 0);
@@ -108,9 +106,6 @@ export class NzCountdownComponent extends NzStatisticComponent implements OnInit
         return current.replace(
           new RegExp(`${name}+`, 'g'),
           (match: string) => {
-            if (name === 'S') {
-              console.log(match);
-            }
             return padStart(value.toString(), match.length, '0');
           }
         );
diff --git a/components/statistic/nz-statistic.component.ts b/components/statistic/nz-statistic.component.ts
index ab6c2edac7a..35ec0276b30 100644
--- a/components/statistic/nz-statistic.component.ts
+++ b/components/statistic/nz-statistic.component.ts
@@ -1,12 +1,11 @@
 import {
   ChangeDetectionStrategy,
-  ChangeDetectorRef,
   Component,
   Input,
   TemplateRef,
   ViewEncapsulation
 } from '@angular/core';
-import { NzStatisticConfig, NzStatisticValueType } from './nz-statistic-config';
+import { NzStatisticValueType } from './nz-statistic-config';
 
 @Component({
   changeDetection: ChangeDetectionStrategy.OnPush,
@@ -25,10 +24,7 @@ export class NzStatisticComponent {
   @Input() nzTitle: string | TemplateRef<void>;
   @Input() nzValue: NzStatisticValueType;
   @Input() nzValueStyle = {};
-  @Input() nzDecimalSeparator: string = '.';
-  @Input() nzGroupSeparator: string = ',';
+  @Input() nzDecimalSeparator = '.';
+  @Input() nzGroupSeparator = ',';
   @Input() nzValueTemplate: TemplateRef<{ $implicit: NzStatisticValueType }>;
-
-  constructor(protected cdr: ChangeDetectorRef) {
-  }
 }