Abstract: The reliability of air-gap detonation transmission interface of partition initiator is analyzed by NESSUS software in this paper. The reliability under given design condition was obtained. The sensitivity analysis and importance analysis about those parameters which affect the interface reliability were done. It is found that, the factors of detonation velocity and density of detonator output charge, thickness and density of detonator cover and the critical explode pressure of transmit charge have relatively greater effect on the reliability. The consistency of these parameters should be guaranteed when selecting materials and proceesing products.