Abstract: In order to optimize the engine, working principle of the single-cylinder liquefied petroleum gas engine based on the ZS1100 diesel engine was studied. The power performance and working process of the LPG engine was investigates by the testing and simulation computation. By optimizing the parameters of the mixture chamber of the LPG delivery system, designing the parameters of the combustion system and controlling the ignition advanced angle, the performances of the LPG engine were optimized. The testing results show that the LPG engine has the better overall performances equipping with the ignition advanced angle adjusted equipment. Through modeling the heat release rate and analyzing the computation results, the direct information about the working process of the LPG engine can be got. The results can provide reference for improvement of LPG engine.