Penetration of distributed generation（DG） makes the power flow of distribution network change greatly， so the traditional relay protection of distribution network is no longer suitable. Based on the character that some bus nodes can judge the fault direction by current measurement in DG system， this paper presents an adaptive searching algorithm for dividing relevant fault area. To realize the selectivity， communication system should be used in the distributed relay protection system. The presented distributed and self-adaptive algorithm can reduce the waiting time of protection information in channel of communication system. The protection can operate correctly just based on the collected fault information about the relevant fault area. This paper uses IEC 61850 to solve the problems of heterogeneous and asynchronous transmission in the distributed relay protection system. The experiment results prove the validity of the presented algorithm.