when digital circuits are in space radiation environment,faults may occur by the influence of single event upsets (SEU).Because devices do not have enough ability to resist radiation,redundancy technology must be adopted in spaceflight application.Triple modular redundancy technology is an effective fault tolerant technology to resist SEU,while it costs huge hardware resources.This paper proposes a structure which is based on the inherent characteristics of synchronization within triple modular redundancy state machine.This paper analyzes the structure differences between the novel one and the traditional one,and established the reliability model which is based on the new TMR structure,finally hardware resources cost was analyzed.Compared with traditional structure,simulation result indicates that the novel structure can save gigantic hardware resources.Under specific application,synchronization point can be set according to the compromise of reliability requirement and resources occupation consideration.