RFID security and privacy issues have been intensively studied in the research field, the authentication between RFID reader and tag is the fundamental them. Most of the existing authentication protocols draw assumptions on classic primitives. Since tags have small capacities, the security mechanisms which are in use in computer networks and communication are not suitable. In this paper, we compare and analyze recent technical research on the problems of privacy and security. It consists of security mechanism, threats and performance evaluation, etc.