In this paper, with the ANSYS, stress distribution and safety factor of connecting rod were analyzed by using 3D finite element method. The results show that the exposed destructive position is the transition location of big end and connecting rod shank at maximum compression condition and maximum stretch condition. Maximum stress is 353MPa. Safety factor is 2.22. Maximum deformation is 0.0728mm. Based on the analysis, the structure of connecting rod is improved. Safety factor of connecting rod increase 12%.