This paper studied the principles of multi body dynamics calculation and provided kinematic equations, established a multi flexible body full aircraft model based on ADAMS for the integration of landing gear and flexible body, studied the asymmetric landing gear load of civil aircraft, and verified the applicability of the integrated multi flexible body full aircraft model by comparing it with the landing gear load calculated by traditional landing dynamics methods. Based on simulation results, the impact of asymmetric landing on landing gear load was analyzed, and strategies to reduce landing gear load were proposed. The results show that the maximum compression of asymmetric landing buffer is greater than that of symmetric landing, the maximum load of asymmetric landing buffer is greater than that of symmetric landing, and under asymmetric landing conditions, the maximum load on the landing gear on the first landing side is significantly greater than that on the landing gear on the second landing side. Asymmetric landing is not conducive to the structural safety of the landing gear and the aircraft body, so it is necessary to avoid asymmetric landing situations as much as possible in the operation of civil aircraft.