diff --git a/src/components/ContextMenu/DropdownMenu.js b/src/components/ContextMenu/DropdownMenu.js
index cb249f03..f2855473 100644
--- a/src/components/ContextMenu/DropdownMenu.js
+++ b/src/components/ContextMenu/DropdownMenu.js
@@ -134,6 +134,12 @@ export const DropdownMenu = ({
     <MenuItem divider />
     {selEnabled && (
       <React.Fragment>
+        <MenuItem eventKey="addToBlacklist" onSelect={onMenuSelect}>
+          {i18n("cmenu_addToBlacklist")}
+        </MenuItem>
+        <MenuItem eventKey="removeFromBlacklist" onSelect={onMenuSelect}>
+          {i18n("cmenu_removeFromBlacklist")}
+        </MenuItem>
         <MenuItem className="DropdownMenu__Item--quickSearch">
           {i18n("cmenu_quickSearch")}{" "}
           <span style={{ float: "right" }}>&#9658;</span>
diff --git a/src/components/ContextMenu/PrefModal.js b/src/components/ContextMenu/PrefModal.js
index 711d61cc..ffec9204 100644
--- a/src/components/ContextMenu/PrefModal.js
+++ b/src/components/ContextMenu/PrefModal.js
@@ -46,7 +46,10 @@ const DEFAULT_PREFS = {
   fontSize: 20,
   termSize: { cols: 80, rows: 24 },
   termSizeMode: "fixed-term-size",
-  bbsMargin: 0
+  bbsMargin: 0,
+
+  // blacklist
+  blacklist: []
 };
 
 const PREF_STORAGE_KEY = "pttchrome.pref.v1";
@@ -64,7 +67,7 @@ export const readValuesWithDefault = () => {
   }
 };
 
-const writeValues = values => {
+export const writeValues = values => {
   try {
     window.localStorage.setItem(
       PREF_STORAGE_KEY,
diff --git a/src/components/ContextMenu/index.js b/src/components/ContextMenu/index.js
index ffbc1934..64fe9222 100644
--- a/src/components/ContextMenu/index.js
+++ b/src/components/ContextMenu/index.js
@@ -23,6 +23,10 @@ const menuHandlerByEventKey = {
   copy: (pttchrome, { selectedText }) => pttchrome.doCopy(selectedText),
   copyAnsi: pttchrome => pttchrome.doCopyAnsi(),
   paste: pttchrome => pttchrome.doPaste(),
+  addToBlacklist: (pttchrome, { selectedText }) =>
+    pttchrome.doAddToBlacklist(selectedText),
+  removeFromBlacklist: (pttchrome, { selectedText }) =>
+    pttchrome.doRemoveFromBlacklist(selectedText),
   searchGoogle: (pttchrome, { selectedText }) =>
     pttchrome.doSearchGoogle(selectedText),
   openUrlNewTab: (pttchrome, { aElement }) =>
diff --git a/src/js/en_US_messages.js b/src/js/en_US_messages.js
index f1336726..b2fc8edd 100644
--- a/src/js/en_US_messages.js
+++ b/src/js/en_US_messages.js
@@ -41,6 +41,12 @@ export const en_US = {
   "cmenu_selectAll": {
     "message": "Select all"
   },
+  "cmenu_addToBlacklist": {
+    "message": "Add ID to blacklist"
+  },
+  "cmenu_removeFromBlacklist": {
+    "message": "Remove ID from blacklist"
+  },
   "cmenu_searchGoogle": {
     "message": "Search Google for"
   },
diff --git a/src/js/pttchrome.js b/src/js/pttchrome.js
index c4329bb3..11565975 100644
--- a/src/js/pttchrome.js
+++ b/src/js/pttchrome.js
@@ -14,6 +14,7 @@ import { setTimer } from './util';
 import PasteShortcutAlert from '../components/PasteShortcutAlert';
 import ConnectionAlert from '../components/ConnectionAlert';
 import ContextMenu from '../components/ContextMenu';
+import { readValuesWithDefault, writeValues } from "../components/ContextMenu/PrefModal";
 
 function noop() {}
 
@@ -352,6 +353,20 @@ App.prototype.switchToEasyReadingMode = function(doSwitch) {
   this.view.conn.send(unescapeStr('^L'));
 };
 
+App.prototype.doAddToBlacklist = function(str) {
+  const values = readValuesWithDefault()
+  values.blacklist = [...new Set([...values.blacklist, str.trim()])];
+  writeValues(values);
+  console.log('add to blacklist', str);
+};
+
+App.prototype.doRemoveFromBlacklist = function(str) {
+  const values = readValuesWithDefault()
+  values.blacklist = values.blacklist.filter((user) => user !== str.trim());
+  writeValues(values);
+  console.log('remove from blacklist', str);
+};
+
 App.prototype.doCopy = function(str) {
   if (str.indexOf('\x1b') < 0) {
     str = str.replace(/\r\n/g, '\r');
diff --git a/src/js/term_buf.js b/src/js/term_buf.js
index 445e80d0..a9ec6efb 100644
--- a/src/js/term_buf.js
+++ b/src/js/term_buf.js
@@ -3,6 +3,7 @@
 import { Event } from './event';
 import { ColorState } from './term_ui';
 import { u2b, b2u, parseStatusRow, parseListRow } from './string_util';
+import { readValuesWithDefault } from '../components/ContextMenu/PrefModal';
 
 const termColors = [
   // dark
@@ -360,6 +361,41 @@ TermBuf.prototype = {
     this.queueUpdate();
   },
 
+
+  filterBlacklist: function() {
+    const { blacklist } = readValuesWithDefault();
+
+    var cols = this.cols;
+    var rows = this.rows;
+    var lines = this.lines;
+    for (var row = 0; row < rows; ++row) {
+      var line = lines[row];
+      // search comment blacklist
+      if (line[2].ch === ' ') {
+        const idText = line
+          .filter((ch) => ch.bg === 0 && ch.fg === 3 && ch.bright)
+          .map((ch) => ch.ch).join('').trim();
+
+        if (!idText) continue;
+        if (blacklist.includes(idText)) {
+          for (var col = 0; col < cols; ++col) {
+            const ch = line[col];
+            // set id to red
+            if (ch.bg === 0 && ch.fg === 3 && ch.bright) {
+              ch.fg = 1;
+              ch.needUpdate = true;
+            }
+            // set text to ' '
+            if (ch.bg === 0 && ch.fg === 3 && !ch.bright) {
+              ch.ch = ' ';
+              ch.needUpdate = true;
+            }
+          }
+        }
+      }
+    }
+  },
+
   updateCharAttr: function() {
     var cols = this.cols;
     var rows = this.rows;
@@ -787,6 +823,8 @@ TermBuf.prototype = {
     clearTimeout(this.timerUpdate);
     this.timerUpdate = null;
 
+    this.filterBlacklist();
+
     if (this.changed) { // content changed
       this.updateCharAttr();
 
diff --git a/src/js/zh_TW_messages.js b/src/js/zh_TW_messages.js
index b4a3d301..7e430c9d 100644
--- a/src/js/zh_TW_messages.js
+++ b/src/js/zh_TW_messages.js
@@ -38,6 +38,12 @@
   "cmenu_paste": {
     "message": "貼上"
   },
+  "cmenu_addToBlacklist": {
+    "message": "ID 加到黑名單"
+  },
+  "cmenu_removeFromBlacklist": {
+    "message": "從黑名單移除 ID"
+  },
   "cmenu_selectAll": {
     "message": "全選"
   },