The invention provides a self-start control method of a mobile power supply system. The method uses a power supply conversion module. The method comprises the steps that A, a battery management system and a DSP controller are started; B, an energy storage battery is detected; and C, the DSP controller controls an energy storage inverter to output alternating current voltage for power supply. Compared with the prior art, the self-start control method of the mobile power supply system, which is provided by the invention, realizes safe, reliable and uninterrupted power supply of the mobile power supply system.