The access of distributed new energy generation device in modern distribution network makes the traditional three-section current protection difficult to realize. The differential protection needs the laying of optical fiber infrastructures, and its very high construction and maintenance costs make its wide application difficult. The ultra-low delay of 5G communication makes it possible to realize the differential protection of data transmission channels in the power grid, which can be a solution to the problem of high optical-fiber costs. However, the uncertainty of delay and jitter of 5G communication has a negative impact on the calculation accuracy of protection action criterion. To solve this problem, the dynamic time wrapping (DTW) algorithm is used to tolerate the time delay and jitter, and a differential protection criterion based on DTW distance is constructed to eliminate the influence of transmission delay and jitter on calculation and comparison of differential protection. Finally, the influence of parameter selection on the result is analyzed by simulation, and the validity of differential protection criterion algorithm based on DTW distance is verified.