Because the various cosmic radiation in space leads the spaceborne equipment to produce some reliability problems, the application of high performance digital signal processor (DSP) is constrained in the aerospace. Therefore measures need to be taken for fault-tolerant processing. But the soft harden or reinforcement algorithm makes program to repeat calculation and increase the system energy cost. This paper, based on C6748 DSP platform, studies the power consumption optimization method in detail. The experimental results show that this method can significantly reduce the system energy cost and enhance the execution efficiency under the conditions of ensuring error detection rate.