By safety analysis, the interval time of flight control PBIT (power-up built-in test) for civil aircraft is supposed as 20 FH(Flight Hour), which can not cover 24 hours. If the utilization rate of aircraft is high in a whole day, a FLT CTRL PBIT EXPIRED message may be displayed before doing flight control PBIT test next time. To improve the maintenance performance of aircraft, it is necessary to have a safety analysis for flight control PBIT. The safety analysis result shows that it can improve the interval time of flight control PBIT as longer as 30 FH by means of building fault trees of related flight control failure condition and updating exposure time of flight control PBIT events, and under the failure probability requirement of category I~IV flight control failure condition and 1 in 1000 criterion.