In the electric power system operation, various types of failure can happen.Detecting the fault location in the case of failures of the distribution network which requires continued power. this paper adopts TWACS communication technology to detect faults, according to the recorded message of the substation when a fault occurs, combining the use of positive-sequence differential current unit value with two-terminal fault location algorithm based on the detection of parameters confirms the fault location. After the failure occures, using TWACS technology to identify faults and transfer fault information, the first is section targeting, then accurately locating the fault location in the fault zone, and thus rapid troubleshooting. Finally, collecting the Matlab simulation data and using examples verify the feasibility of the method.