The present invention provides an OPLC fault location method based on the DS evidence theory, and belongs to the technical field of intelligent grid detection. The purpose of the present invention isto provide an OPLC fault location method based on the DS evidence theory by using the DS evidence theory to fuse the confidence when the cable and the optical cable fail at the same location at the same time, wherein the fused confidence at the peak value is the most likely fault location. The method provided by the present invention is characterized in that: the cable and the optical cable are used to locate the fault so as to obtain a location result, the cable detection and the optical cable detection are used to measure the OPLC fault location so as to obtain true value distribution, and according to the DS evidence theory, confidence data is fused to obtain a fault location interval. The DS evidence theory fusion method provided by the present invention can solve the problem of difficulty of decision-making brought to the inspector due to inconsistent location results between the cable and the optical cable caused by the location error under the condition that the cable detectionalone or the optical cable detection alone cannot detect the fault location accurately when the cable and the optical cable simultaneously fail at the same location, the accuracy of OPLC fault location under this condition can be effectively improved, and uncertainty of determination can be greatly reduced.