diff --git a/backend/blockchain_listener.py b/backend/blockchain_listener.py
new file mode 100644
index 0000000..bd8db44
--- /dev/null
+++ b/backend/blockchain_listener.py
@@ -0,0 +1,119 @@
+from web3 import Web3
+from bot import BankBot
+
+SBT_ADDRESS = ''
+ABI = [
+        {
+          "anonymous": False,
+          "inputs": [
+            {
+              "indexed": True,
+              "internalType": "address",
+              "name": "client",
+              "type": "address"
+            },
+            {
+              "indexed": True,
+              "internalType": "address",
+              "name": "bank",
+              "type": "address"
+            },
+            {
+              "indexed": False,
+              "internalType": "uint256",
+              "name": "id",
+              "type": "uint256"
+            },
+            {
+              "indexed": False,
+              "internalType": "uint256",
+              "name": "amount",
+              "type": "uint256"
+            }
+          ],
+          "name": "Repay",
+          "type": "event"
+        },
+        {
+          "anonymous": False,
+          "inputs": [
+            {
+              "indexed": True,
+              "internalType": "address",
+              "name": "client",
+              "type": "address"
+            },
+            {
+              "indexed": True,
+              "internalType": "address",
+              "name": "shop",
+              "type": "address"
+            },
+            {
+              "indexed": True,
+              "internalType": "address",
+              "name": "bank",
+              "type": "address"
+            },
+            {
+              "indexed": False,
+              "internalType": "uint256",
+              "name": "id",
+              "type": "uint256"
+            },
+            {
+              "indexed": False,
+              "internalType": "uint256",
+              "name": "amount",
+              "type": "uint256"
+            }
+          ],
+          "name": "Borrow",
+          "type": "event"
+        }
+    ]
+
+class Listener():
+    def __init__(self, bot: BankBot) -> None:
+        self.w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:7545'))
+        self.contract = self.w3.eth.contract(address=SBT_ADDRESS, abi=ABI)
+        self.bot = bot
+
+    def handle_repay_event(self, event):
+        print("Repay Event received:")
+        print(event['args'])
+        print("---")
+
+        args = event['args']
+        if args['client'] in self.bot.clients:
+            chat_id = self.bot.clients[args['client']]
+            self.bot.updater.bot.send_message(chat_id=chat_id, text="已經收到您編號 #{} 的帳款，共 {} ETH.".format(
+                args['id'], int(args['amount'])/(10**18)
+            ))
+
+    def handle_borrow_event(self, event):
+        print("Borrow Event received:")
+        print(event['args'])
+        print("---")
+
+        args = event['args']
+        if args['client'] in self.bot.clients:
+            chat_id = self.bot.clients[args['client']]
+            self.bot.updater.bot.send_message(chat_id=chat_id, text="您已經透過本銀行向 {} 支付 {} ETH. 帳款編號(#{})".format(
+                args['shop'], int(args['amount'])/(10**18), args['id']
+            ))
+        
+        if args['shop'] in self.bot.clients:
+            chat_id = self.bot.clients[args['shop']]
+            self.bot.updater.bot.send_message(chat_id=chat_id, text="本銀行已經先替客戶 {} 向您支付 {} ETH. 帳款編號(#{})".format(
+                args['client'], int(args['amount'])/(10**18), args['id']
+            ))
+
+    def start(self):
+        borrow_event_filter = self.contract.events.Borrow.create_filter(fromBlock='latest')
+        repay_event_filter = self.contract.events.Repay.create_filter(fromBlock='latest')
+        while True:
+            for event in borrow_event_filter.get_new_entries():
+                self.handle_borrow_event(event)
+            for event in repay_event_filter.get_new_entries():
+                self.handle_repay_event(event)
\ No newline at end of file
diff --git a/backend/bot.py b/backend/bot.py
index a660b94..dc26d54 100644
--- a/backend/bot.py
+++ b/backend/bot.py
@@ -10,7 +10,7 @@ from telegram.ext import MessageHandler, CallbackContext, CommandHandler, Filter
 import json
 import os
 
-TOKEN = "6207011315:AAH-J0zjPPd_mDPN1_pCgll0w-pZtlJXYVY"
+TOKEN = ""
 
 class BankBot():
     def __init__(self):
@@ -19,6 +19,7 @@ class BankBot():
         self.dispatcher.add_handler(CommandHandler('start',   self.start))
         self.dispatcher.add_handler(CommandHandler('add',   self.add))
         self.dispatcher.add_handler(MessageHandler(Filters.text, self.echo))
+        self.clients = {}
 
         if os.path.isfile('./client.json'):
             with open("client.json") as fp:
@@ -43,7 +44,7 @@ class BankBot():
             self.clients[address] = update.effective_chat.id
             with open('client.json', 'w') as fp:
                 json.dump(self.clients, fp)
-            context.bot.send_message(chat_id=update.effective_chat.id, text="開始追蹤 {} 的商店收款通知".format(address))
+            context.bot.send_message(chat_id=update.effective_chat.id, text="開始追蹤 {} 的出入帳通知".format(address))
 
     def start(self, update, context):
         context.bot.send_message(chat_id=update.effective_chat.id, text="Hi, 這是暨大區塊鏈銀行 Telegram Bot\n\n/add YOUR_ADDRESS: 追蹤出入帳通知")
\ No newline at end of file
diff --git a/backend/main.py b/backend/main.py
index 0ab862a..9bdbdf1 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -5,6 +5,7 @@ from flask_cors import CORS
 from bot import BankBot
 import time
 import threading
+from blockchain_listener import Listener
 
 app = Flask(__name__)
 CORS(app)
@@ -182,3 +183,6 @@ if __name__ == '__main__':
 
     flask_thread = threading.Thread(target=start_flask)
     flask_thread.start()
+
+    listener = Listener(bot)
+    listener.start()
\ No newline at end of file