Based on the advances in laptop technologies and the mobility characteristics, laptops have become a vital device used at various places. Usually, numerous sensitive files such as credit card numbers and Web cookies are stored on laptops for convenient usage. However, if a laptop is stolen, the data stored on it is easily leaked; which may cause serious consequences. Encrypting files by encryption keys is a general solution; however, if the decryption keys are also stored on laptops, the files can also be decrypted by adversaries easily. To solve this problem, this paper proposes the Mobile Encryption for Laptop data Protection (MELP) system. MELP includes the design of an online server and mobile phone, and encrypts each sensitive file by a file system encryption key, which is further sequentially encrypted twice by the phone's and server's encryption keys. The reason of adopting a mobile phone is that at least one simple confirmation of execution must be performed by a user, and the reason of adopting an online server is that if both user's laptop and mobile phone are stolen, users can still disable the online decryption process on the server.