Abstract: Absrtact: In order to effectively solve the problem of vehicle pollution and long distance and large slope transportation, a new type of mine double-electric trolley auxiliary transportation system is put forward. The system is composed of power supply system, contact net system, charging station, collector and double electric vehicle. It has three operation modes: quick charging, stringing and mixing. This paper puts forward the key technical indexes of each subsystem, and expounds three operation modes in detail. Finally, the auxiliary transportation system of three key technologies: DC750V traction substation capacity and power supply arm matching technology, DC750V network technology, contact and further study on calculating the vehicle battery type and capacity of electric double, and the corresponding solutions, provide technical support for the realization of the future mine trolley auxiliary transportation system.