The mobile substation, manufactured by Ningbo Tianan Transformation Co., Ltd., is applied to replace the conventional substation in case of emergency, help to relieve shortage of power supply capacity in heavy load season, put into operation as the temporary substation. It has function that replaces the conventional substation and resumes the power supply. It could be into operation at once on site after the connection of input and output cable only. The mobile substation provides with prominent advantages, such as simple and compact structure, convenient to move, reliable function, easy to operation and high intelligence. Prefabricated semi-trailer vehicle-mounted mobile substation can be designed according to users’ requirements, and can also configure to single or double or multi vehicles on the basis of users’ service condition.