In view of the multiple structure failure modes appeared previously in experiments,we added a structure reliability prediction under multi-failure mode based on the traditional electronics prediction when implementing system reliability prediction to a new type actuator system.Firstly,the Expert Grading Allocation Method was used to allocate system reliability index to the corresponding modules and components.Then,the reliability index of electronic components was obtained by Component Counting Method,and the structure reliability index under each failure mode was obtained by FOSM method.Thus the system reliability index was obtained.The prediction results show that:1) The reliability indexes of design scheme achieve the requirement of reliability index allocated for the missile;and 2) The reliability index of ball bearing screw under multi-failure mode is lower than that of the other electronics modules,which is consistent with the previous failure phenomenon in experiments.