In view of the problems existing in the present transportation ways of coal mine, a kind of new auxiliary haulage system has been designed, which can achieve the going there and back transportation only by using one winch in the multi-slope and undulating roadway. And according to the requirements of safety production of coal mine, the non-wheeled supply mine car without anti-car device and the safety interlock system of wheeled supply mine car have been designed. Meanwhile, finite element analysis software is adopted to check and analyze the locking pawl strength of the safety interlock system with wheeled supply mine car. The analyzing result shows that the locking pawl can completely stand the impact loading when the mine car sliding down. The haulage costs and the occurrence of security incidents have been reduced when the designed system is applied to coal mine. Engineering practice shows that the good results have been achieved.