In order to study the reliability of the aircraft hatch lock mechanism closing system, this paper choose an aircraft hatch lock mechanism as an example, establishes the simulation model of the mechanism through LMS, and studies the maximum hydraulic pressure failure and the time-failure modes during the closing process of the lock mechanism. Considering the correlation between the two failure modes, based on the important sampling method and B-P neural network method, the reliability of the aircraft hatch lock mechanism with multiple failure modes is calculated. Comparing the simulation results of these two methods with the results of the traditional Monte Carlo method, we can conclude that the above two methods for calculating the reliability of the aircraft door lock mechanism are reasonable, and the error range is within 3%. The computational efficiency of the two methods is improved compared with the traditional methods. Among them, the BP neural network method is more accurate and efficient than the important sampling method, and is more suitable for studying the reliability of the aircraft door lock mechanism.