Experimental model analysis was used to determine the different frequencies of the CZ480 diesel engine body and the deformation of the body was calculated by software STAR 5.0. The results show that there is a torsion formation of the engine body in the first and the fourth models, and there is also a bend torsion deformation in the second, third, fifth and sixth stage models. These deformations have sighificant effects on engine performance. There is also a vibration along the axes of the engine body, and the shape of the vibration is elliptical. This causes the leakage of gas and lubricating oil from cylinder. This is also the main reason that damage to the cylinder line and the engine body occurs. This provides a basis for analysis of the vibration of engine body by FIM model analysis. It also provides a theoretical basis for desigh improvement of the engine body.