In order to determine the key parts of the mechanical damage detection of leveling and erecting device of a missile launch vehicle， the finite element stress analysis experiment of load-bearing parts is carried out. The forces of the leveling cylinder and the lifting load bearing lug base are analyzed and used as the mechanical input of the finite element simulation. The three-dimensional structural model is established and imported into the ANSYS simulation software to carry out the finite element simulation of the leveling and lifting process. The results show that the inner side of the leveling cylinder， the circular hole of the load bearing lug and the connection between the base and the rib plate are the stress concentration areas， which should be focused on damage detection.