Research conclusions ; The research proves that the locomotive load current distribution ratio is the same to the current distribution ration under short-circuit condition. So it is workable to make research with locomotive load current value instead of short-circuit parameters. The verified parameters calculated with locomotive load apply to the protective value of the failure distance and locate the actual failure point. Establish the T-R short-circuit ratio curve graph of each section of the whole line by using a large amount of data，and then confirm the failure point location by seeking table method. This technology could be applied to up and down all-paralleling AT feeding systems distance measurement accuracy verification and formulas of newly built and operational railway passenger dedicated line to verify parameters.