To solve the deformation problem of the linkage mechanism in the process of retracting and unwinding the linkage landing gear of the door， according to its motion characteristics， the kinematics and dynamics models of the linkage mechanism are established based on the D-H coordinate transformation method and the second type of Lagrange equation. The deformation of the connecting rod caused by the sudden change of the hinge moment of the mechanism is solved through numerical simulation. To solve the fault problem， firstly， the influence of the spatial installation position and rod length change of the linkage mechanism on the mechanical properties of the mechanism is analyzed， the key positions are found， an optimization model considering the attitude change is established according to the spatial position relationship of the hinge rotation axis， and the spatial position and attitude of the hinge are optimized by particle swarm optimization， the optimal installation point is found， and the results before and after optimization are compared. The results show that after optimization， the rotation speed of the hinge is abruptly reduced by 80.0%， the torque of the hinge is reduced by 74.8%， the movement of the mechanism is more stable， and the deformation is avoided.