A new electronic control unit （ECU） for high pressure common rail diesel engine was developed base on the powerful microcontroller MPC5xx in this paper. The ECU is composed of such modules as microcontroller, sensor signal processing, power supply, driving circuit and communication interface. The function and structure of each module are discussed in this paper. Some ways to improve the reliability performance and electro magnetic compatibility of this ECU were also proposed in this paper. The experiments show that it takes only 0.2 ms for the current to rise from 0 A to peak current 10 A and 0.3 ms for the current to fall from hold current 5 A to 0.1 A when driving the common rail diesel solenoid valve. The ECU can fully meet the requirement of high pressure common rail diesel fuel injection system.