Research conclusions:This paper analyzes the principle of the traction return system of TRNF traction network． From the simulation calculation and analysis of the tested data of the return current to the Chongshan substation of the TRNF traction network with return wire for the Chengdu － Dujiangyan Passenger Dedicated Line，it can be seen using the TRNF traction network with return wire can significantly improve the distribution form of the return current system，reduce the proportion of the return current of the rail － earth and cut the impacts on the traction power supply equipment and communications signals equipments． Thus it can provide the design basis for selection of the equipments for the substation and communications signaling systems．