The timing design of the missile launch process determines the operational response time of the missile weapon system, and the bus network delay is an important design basis for the timing design. The existing bus delay testing methods only aims at a single component. In order to realize the delay test of system-level bus network, a timing simulation platform for electrical system of intelligent ammunition is built. The system hardware architecture, software modeling and simulation are designed in detail. Through the real part in the ring of a certain missile firing timing simulation test, the diagnostic test of system-level bus network delay is realized. The test results show that the system can optimize the firing timing of a certain missile.