Recently, Radio Frequency Identification (RFID) has been widely used. A lightweight security authentication protocol for mobile RFID is proposed to aim at the problems of high complexity and system security in existing mobile RFID authentication protocols. The tag identity is encrypted by the matrix’s arrangement and combination of column vectors based on column pseudonyms, which can effectively reduce tag computational complexity. The tag is required to mainly store its identity and shared keys, which can effectively reduce tag storage complexity. During the authentication process, the proposed protocol generates dynamic authentication keys without changing shared keys, which are different in each session. The protocol uses XOR operation to transfer privacy data based on the dynamic authentication keys. This method can effectively reduce the computational complexity of the protocol while protecting privacy data. The protocol requires the receiver to verify the random number in time after receiving information, which can effectively solve the system security problem. Formal proof and analysis results show that the proposed protocol has good security and can resist attacks. The experimental results indicate that the protocol has low complexity, which can effectively reduce the burden of tag operation and storage. It has good value for mobile RFID systems.