diff --git a/CHANGELOG.md b/CHANGELOG.md
index 72ad5757..8eb3b458 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@ and this project adheres to
 
 ## [Unreleased]
 
+## Fixed
+
+- 🐛(db) fix users duplicate #316
+
 
 ## [1.5.0] - 2024-10-09
 
diff --git a/src/backend/core/migrations/0007_fix_users_duplicate.py b/src/backend/core/migrations/0007_fix_users_duplicate.py
new file mode 100644
index 00000000..50139299
--- /dev/null
+++ b/src/backend/core/migrations/0007_fix_users_duplicate.py
@@ -0,0 +1,128 @@
+# Generated by Django 5.1.1 on 2024-10-10 11:45
+
+from django.db import migrations
+
+procedure = """
+DO $$
+DECLARE
+    user_email TEXT;
+BEGIN
+    -- Step 1: Create a temporary table (without the unique constraint)
+    -- impress_document_access
+    DROP TABLE IF EXISTS impress_document_access_tmp;
+    CREATE TEMP TABLE impress_document_access_tmp AS
+    SELECT * FROM impress_document_access;
+    
+    -- impress_link_trace
+    DROP TABLE IF EXISTS impress_link_trace_tmp;
+    CREATE TEMP TABLE impress_link_trace_tmp AS
+    SELECT * FROM impress_link_trace;
+
+    -- Step 2: Loop through each email that appears more than once
+    FOR user_email IN
+      SELECT email
+      FROM impress_user
+      GROUP BY email
+      HAVING COUNT(email) > 1
+    LOOP
+      -- Step 3: Update user_id in the temporary table based on email
+      -- For impress_document_access
+      UPDATE impress_document_access_tmp
+      SET user_id = (
+        SELECT id
+        FROM impress_user
+        WHERE email = user_email
+        LIMIT 1
+      )
+      WHERE user_id IN (
+        SELECT id
+        FROM impress_user
+        WHERE email = user_email
+      );
+
+      -- For impress_link_trace
+      UPDATE impress_link_trace_tmp
+      SET user_id = (
+        SELECT id
+        FROM impress_user
+        WHERE email = user_email
+        LIMIT 1
+      )
+      WHERE user_id IN (
+        SELECT id
+        FROM impress_user
+        WHERE email = user_email
+      );
+      
+      -- update impress_invitation
+      UPDATE impress_invitation
+      SET issuer_id = (
+        SELECT id
+        FROM impress_user
+        WHERE email = user_email
+        LIMIT 1
+      )
+      WHERE issuer_id IN (
+        SELECT id
+        FROM impress_user
+        WHERE email = user_email
+      );
+      
+      DELETE FROM impress_user
+      WHERE id IN (
+        SELECT id
+        FROM impress_user
+        WHERE email = user_email
+      )
+      AND id != (
+        SELECT id
+        FROM impress_user
+        WHERE email = user_email
+        LIMIT 1
+      );
+
+      RAISE NOTICE 'Processed updates for email: %', user_email;
+    END LOOP;
+		
+    -- Step 4: Remove duplicate rows from the temporary table, keeping only one row per (document_id, user_id)
+    -- For impress_document_access
+    DELETE FROM impress_document_access_tmp a
+    USING impress_document_access_tmp b
+    WHERE a.ctid < b.ctid  -- Keep one row
+    AND a.document_id = b.document_id
+    AND a.user_id = b.user_id;
+
+    -- Step 5: Replace the original table with the cleaned-up temporary table
+    TRUNCATE TABLE impress_document_access;
+
+    -- Insert cleaned-up data back into the original table
+    INSERT INTO impress_document_access
+    SELECT * FROM impress_document_access_tmp;
+    
+    -- For impress_link_trace
+    DELETE FROM impress_link_trace_tmp a
+    USING impress_link_trace_tmp b
+    WHERE a.ctid < b.ctid  -- Keep one row
+    AND a.document_id = b.document_id
+    AND a.user_id = b.user_id;
+
+    -- Step 5: Replace the original table with the cleaned-up temporary table
+    TRUNCATE TABLE impress_link_trace;
+
+    -- Insert cleaned-up data back into the original table
+    INSERT INTO impress_link_trace
+    SELECT * FROM impress_link_trace_tmp;
+		
+    RAISE NOTICE 'Update and deduplication process completed.';
+END $$;
+"""
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0006_add_user_full_name_and_short_name'),
+    ]
+
+    operations = [
+        migrations.RunSQL(procedure),
+    ]