The invention relates to the field of control of hybrid power automobiles, in particular to a mild hybrid power automobile power supply control method. The mild hybrid power automobile power supply control method comprises the steps that after an ignition lock ON-gear switch is powered on, initialization is performed; after the initialization is completed, whether powering-on conditions are met or not is detected; if so, powering-on parameters are obtained, and powering on is performed according to the electrifying parameters; in the electrifying process, whether powering-off conditions are met or not is detected, if so, a powering-off flow is executed. By the adoption of the mild hybrid power automobile power supply control method, the power performance and comfort of vehicle starting are improved.