Abstract: Based on the stress-strength interference theory, a new method for reliability design of initiating devices was presented to solve the randomicity of input energy. To achieve a reasonable design of fire reliability and safety reliability, the reliability index was transformed into sensitivity distribution parameter with a stress-strength interference model. The reliability design formulas about stress and strength in the normal distribution-normal distribution or lognormal distribution-lognormal distribution were deduced. An application example showes that the product designed with this method can both meet the requirements of fire reliability and safety reliability. It also showes that the new method can play an instructive role in reliability design of initiating devices.