Abstract: In this paper，the relay was selected as a key part by analyzing the fault modes of missile power supply control unit. Based on time series analysis，the mathematical model for fault forecasting was built，and the mathematical model was identified for super-path time and pick-up time of relays. The computing results were obtained and analyzed by comparing the model based on super-path time with pick-up time. The test device of parameter collecting was designed to simulate the loads under the actual working condition. And the forecasting result was validated by the experiment data.

Key words: Missile power supply control unit, Fault forecasting, Time series analysis