To improve the ignition reliability of firearm firing-ignition systems， the Lagrangian-Eulerian fluid-structure coupling method （ALE） was used to establish the ignition model of the firing-ignition systems， and a parametric simulation platform was built. The pressure start time was used as the ignition output performance characteristic parameter to establish the ignition reliability proxy model of the firearm firing-ignition system. The reliability of the firing-ignition systems under the influence of changes in structure and assembly parameters was simulated and studied. At the same time， based on small-caliber rifle firing-ignition system， an ignition system simulation test device was designed， and experimental research on the ignition performance and reliability of the ignition system was carried out to verify the ignition model. The results show that the error between the calculation results of the firearm firing-ignition reliability analysis model and the experimental results is 0.72%， indicating that the model has good accuracy. The influence rule of the average change of each factor on the system reliability is as follows： striking pin protrusion> locking gap> fire table head diameter> primer shell thickness> primer loading depth> firing pin head diameter. The standard deviation change has little impact on system reliability. This study provides theoretical and technical guidance for the reliability design of firearm firing-ignition systems.