The invention belongs to the technical field of mobile substations, and particularly relates to a vehicle-mounted mobile transformer with a position-adjustable outgoing line sleeve. In order to overcome the defect that the width and height exceed the limit in transportation when an existing conventional transformer is applied to a vehicle-mounted mobile substation, the following technical scheme is adopted, namely, the vehicle-mounted mobile transformer with a position-adjustable outgoing line sleeve comprises a transformer body and a high-voltage outgoing line sleeve, the high-voltage outgoing line sleeve comprises an oil-SF6 gas sleeve, an SF6 gas-air sleeve and a connecting device, the oil-SF6 gas sleeve is installed on a high-voltage sleeve base, the connecting device is installed on the oil-SF6 gas sleeve, the SF6 gas-air sleeve is installed on the connecting device, and the SF6 gas-air sleeve can rotate relative to the connecting device so that the position of the SF6 gas-air sleeve is adjustable. The vehicle-mounted mobile transformer has the beneficial effect that the SF6 gas-air sleeve can rotate and is adjustable in position so that the transportation requirements of high-voltage equipment such as 220kV equipment are met.