diff --git a/jog-admin/src/main/resources/db/migration/V1__init_schema.sql b/jog-admin/src/main/resources/db/migration/V1__init_schema.sql
index add1b5a..a55a936 100644
--- a/jog-admin/src/main/resources/db/migration/V1__init_schema.sql
+++ b/jog-admin/src/main/resources/db/migration/V1__init_schema.sql
@@ -30,7 +30,7 @@ CREATE TABLE IF NOT EXISTS sys_user_session (
     id BIGINT AUTO_INCREMENT PRIMARY KEY,
     user_id BIGINT NOT NULL COMMENT '用户ID',
     token VARCHAR(500) NOT NULL COMMENT '访问令牌',
-    device_fingerprint VARCHAR(255) DEFAULT NULL COMMENT '设备指纹',
+    device_fingerprint VARCHAR(100) DEFAULT NULL COMMENT '设备指纹',
     ip_address VARCHAR(50) DEFAULT NULL COMMENT 'IP地址',
     user_agent VARCHAR(500) DEFAULT NULL COMMENT 'User-Agent',
     expire_time DATETIME NOT NULL COMMENT '过期时间',
@@ -48,7 +48,7 @@ CREATE TABLE IF NOT EXISTS sys_login_log (
     result TINYINT NOT NULL COMMENT '结果：0失败 1成功',
     fail_reason VARCHAR(200) DEFAULT NULL COMMENT '失败原因',
     ip_address VARCHAR(50) DEFAULT NULL COMMENT 'IP地址',
-    device_fingerprint VARCHAR(255) DEFAULT NULL COMMENT '设备指纹',
+    device_fingerprint VARCHAR(100) DEFAULT NULL COMMENT '设备指纹',
     created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
     KEY idx_user_id (user_id),
     KEY idx_created_at (created_at)
diff --git a/jog-admin/src/main/resources/db/migration/V4__alter_device_fingerprint_length.sql b/jog-admin/src/main/resources/db/migration/V4__alter_device_fingerprint_length.sql
new file mode 100644
index 0000000..7916a91
--- /dev/null
+++ b/jog-admin/src/main/resources/db/migration/V4__alter_device_fingerprint_length.sql
@@ -0,0 +1,9 @@
+-- V4__alter_device_fingerprint_length.sql
+-- 将 device_fingerprint 列宽从 VARCHAR(100) 扩到 VARCHAR(255)，以容纳更长的设备指纹特征字符串。
+-- 注意：V1 已发布到生产，不能直接修改，因此通过本迁移以 ALTER 形式落地。
+
+ALTER TABLE sys_user_session
+    MODIFY COLUMN device_fingerprint VARCHAR(255) DEFAULT NULL COMMENT '设备指纹';
+
+ALTER TABLE sys_login_log
+    MODIFY COLUMN device_fingerprint VARCHAR(255) DEFAULT NULL COMMENT '设备指纹';