Abstract: Photoelectric encoder CAN bus interface is put forward in order to make photoelectric encoder used in the system which adopts CAN Bus as data transmission method. Firstly, CAN bus interface hardware circuit of photoelectric encoder is designed which is composed of singlechip, CAN bus controller SJA1000, CAN bus transceiver TJA1050 and high-speed optical coupling TLP113 ; secondly, the paper introduces the design of CAN bus interface software consisted of the design of initialization, receiving message and sending message; lastly, the feasibility of photoelectric encoder CAN bus interface is proofed by “USBCAN1”CAN interface card produced by ZLG company. In the test, communication speed rate is 800kbps and one-meter shield twisted pair line is used as the transmission medium; the results show that the photoelectric encoder with CAN bus interface overcomes communication line’s shortcomings of classical photoelectric encoder system . The system can work in automatic measuring and controlling system better as a result of the advantages of more real-time and reliability , high transfer rate , long transfer distance and high resistance.