Aiming at the problem of how to ensure the reliability of electric explosive device (EED) in practical engineering application, a calculation method of ignition current based on Simulink simulation software is proposed. The ignition principle of EED was analyzed, and the influence factors such as the resistance change of ignition circuit cable and the contact resistance of connectors in high temperature environment were comprehensively considered. The ignition current of complex ignition circuit was calculated by simulation and verified by experiments. The results show that the algorithm improves the reliability of initiating explosive device, saves the development cost, and provides a feasible method for the engineering design field.