50%～90%。EGR electronic control system for diesel DL190[CD*2]12 was developed. The hardware and software of EGR electronic control system was designed respectively. The design of hardware includes the ECU design, data signal acquisition processing circuit design, implementing agencies drive circuit design and display circuit design. The design of control software is modular. The engine table tests showed that Nox emission of the ethanol-diesel blend fuel engine DL190—12 equipped with the EGR was reduced by 50%～90% than that of the original diesel.  