Basing on establishing the mechanical model of crankshaft and connecting rod mechanism in reciprocating compressor,the forces of the crankshaft using trditional dynamics analysis method are researched and calculated the changing regularity of crankshaft dynamic load and dangerous point with MATLAB.After that,the FEM method was used to simulate the crankshaft load,determining the state of stress and deformation and the state of static strength and stiffness.The research results ensure the safety and reliability of the part and has a high research value for optimization of crankshaft.