With the mass deployment of the RFID system worldwide in recent years, the security concern of RFID system is becoming more and more important and pressing. However, one of the main standards of RFID technology, EPC Class-1 Generation-2 RFID standard has a very low security level, as analyzed in previous work such as. In this paper, we first have a brief review and fully security analysis of different authentication schemes. Then we propose an improved scheme, with a fully security analysis, the improved scheme proved to be a great improvement in security compared to the current ones. Finally, we also design a simple hardware plan to implement and verify the improved scheme proposed by this paper.