Abstract: The authors studied the electronic control injection fuel-feed system and CDI digital ignition SCM control system implemented on the motor engine by liquefied petroleum gas(LPG) and optimized electronic control parameters in engine dais experiment. Through experiment comparison, the engine with electronic control system has proved to be obviously improved than the carburetor petrol engine in tail exhaust HC and CO in the tail exhaust have decreased by more than 50%. By using substitute fuel the pollution problem of exhaust emission of minitype engine has been further controlled.