The invention relates to an RF (Radio Frequency) card read-write system. The RF card read-write system comprises an RF card read-write module, a processing unit, an encryption/decryption module and a memorizer, wherein the RF card read-write module is used for reading a number of an RF card and encryption card data from the RF card and writing encryption data sent by the processing unit in the RF card; the processing unit is used for detecting the memorizer so as to judge the legality of the RF card, obtaining a sub secret key corresponding to the RF card from the memorizer, using the sub secret key and the encryption card data as data to be decrypted, sending the data to be decrypted to the encryption/decryption module, operating and processing a data clear text, using an operating result of the data clear text and the sub secret key as data to be encrypted, sending the data to be encrypted to the encryption/decryption module, sending the operating result of the data clear text to the memorizer, and sending encrypted data returned from the encryption/decryption module to the RF card read-write module; the encryption/decryption module is used for obtaining the data clear text by decrypting the encryption card data by utilizing the sub secret key, and obtaining the encryption data by encrypting operating result of the data clear text by utilizing the sub secret key; and the memorizer is used for correspondingly memorizing the number of the RF card, the sub secret key and the operating result of the data clear text. According to the RF card read-write system disclosed by the invention, the safety of data memorized by the RF card can be increased.