To study the landing process of civil aircraft, a dynamic model of aircraft landing is established based on the d‘Alembert principle, and numerical simulation analysis of landing gear load is carried out. The applicability of the simulation method is verified by comparing it with landing test results. Based on the simulation analysis results of landing gear load, the vertical load and heading load of the aircraft landing gear are analyzed, and the influence and mechanism of the initial vertical velocity and heading velocity on the landing gear load are analyzed. Suggestions to avoid excessive landing load are proposed. The results show that the vertical load of the landing gear increases first and then decreases, with two peaks during the increase process; the direction and magnitude of the landing gear heading load are in a fluctuating state, ultimately stabilizing near zero values; the vertical load of the landing gear increases with the increase of the initial vertical velocity, while the heading load of the landing gear increases with the increase of the initial heading velocity; the initial vertical velocity and heading velocity should be minimized as much as possible.