A mobile substation comprises a sealing steel shell body and an arc shell, wherein positive pressure of 0.02-0.03MPa is filled to the interior of the sealing steel shell body through liquid nitrogen inflation, the arc shell is welded at the upper end of the sealing steel shell body, a sound insulation and moisture prevention inner plate is arranged inside the sealing steel shell body, an air inlet and an air outlet are arranged at the upper end of the sound insulation and moisture prevention inner plate, an amorphous alloy transformer is arranged in the sound insulation and moisture prevention inner plate, a positive pressure inflation device is arranged inside the sealing steel shell body and comprises an air inlet, an air outlet, a liquid nitrogen inflation tank and valves, the liquid nitrogen inflation tank is connected with the air inlet, the valves are separately arranged on the air inlet and the air outlet and are connected with a programmable logic controller (PLC) through wires, and the PLC is connected with a temperature connector through a wire. By the mobile substation, the effects of moisture prevention, dust prevention and explosion prevention are effectively ensured, meanwhile, the temperature is effectively controlled, the mobile substation has long service lifetime and can be applicable for borehole operation for a long time.