In order to deal with the safety problem of privacy in CPU card and Radio Frequency Identification (RFID) process, this paper proposes an encryption algorithm that combines the Elliptic Curve Crypto-system (ECC) with the Advanced Encryption Standard (AES). This method firstly uses the high efficiency secret-key to encrypt important information, and then use the AES to encrypt the communication information between CPU card and the reader and writer. Thus the important information will be encrypted double in the process of communication, even though attackers get the Radio Frequency CPU card or intercept the communication information, they can’t obtain useful information as quickly as they need. The experimental results show that the method improves the safety of the CPU card and against the attacks during the communication. The proposed mixed encryption algorithm plays an important role in the safety problem of privacy.