Abstract: The dynamic model of the engine shutdown process is estabished. The both calculation formula of the cylinder gas and crankshaft output torque are derived. The 4G15 GDI engine is taken as an example to do simulation calculation and bench experiment. Torque and speed characteristics of the shutdown process is analyzed in detail.Resultsshow that the torque changes are approximate cycle attenuation process. The distribution of the piston stop before the check point within 60°-80°CA is about 90%.This study provide the key information for the next piston position control strategy.