Abstract: To solve the problem of selecting the optimal relay set for hybrid decode-amplify-and-forward cooperative communication, a relay selection algorithm based on the statistical channel information was proposed. First, the parameter calculation of the statistical channel information of each relay was analysed under the equal power allocation. Then the optimal relay set with minimum outage probability was obtained. The simulation results show that the average outage probability of this algorithm is lower than that of the other traditional relay selection algorithmunder the same conditions. In addition, the performance of the system is further improved by the redistribution of the power of the working nodes in cooperative communication.