In a method for protecting data of a mobile phone, the mobile phone includes a storage system. The storage system stores a plaintext file to be encrypted and an international mobile equipment identification (IMEI) number of the mobile phone. The IMEI number of the mobile phone and the plaintext file are read from the storage system. A ciphertext is generated from the plaintext file according to the IMEI number of the mobile phone using an encryption algorithm. The IMEI number of the mobile phone and the ciphertext are read from the storage system when the ciphertext needs to be decrypted. The plaintext file is recovered from the ciphertext according to the IMEI number of the mobile phone using a decryption algorithm.