To provide testing support for independent research and development of the automotive electronic control unit, an engine ECU calibration system which based on the CAN bus communication was developed. The calibration system includes four parts. That’s a calibration system software, communication module, the engine ECU and the engine that to be calibrated and tested. It uses the CAN-bus as the communication which has the main structure of a higher rate. The main achievement is that design the host computer’s table, collect and process the data, design the conversion interface between the standard protocol and a custom protocol, send data, receive data, load data, upload data, programming, acquisition data, and hardware detection, control functions, etc. EFI products in the practical application of the system showed that the system agreed with good universal property, efficient data processing and it is suitable for various ECU products that use different protocol.