In this thesis, we used a encryption mechanism based on AES(Advenced Encryption Standard). Except for this mechanism, we also combine RS-232 Serial Communication Control, Smartcard and EM card which originally used in the Entrance Guard System to implement a new system. Eventually, this new system applies to a certain rental system practically. We also introduce some functions of this rental system based on the encryption mechanism, station initialization, bike rental, bike allocation and bike rental for credit card for example. In addition, we will describe what problems we met and the solutions we introduced to the problems finally.