A power supply control circuit for a switch mode power supply converter, and a power supply control method using the control circuit. The control circuit includes an auxiliary boosting unit, a main control unit and an auxiliary winding unit. The main control unit is configured to control the power switch in a power stage circuit to turn on or to be off, and to supply power to the auxiliary boosting unit. The auxiliary boosting unit is configured to provide auxiliary power for the main control unit, and to self-adaptively adjust the auxiliary boosting unit's own average switching frequency based on a load state of the main control unit. The auxiliary winding unit is configured to couple energy by means of a magnetic element in the power stage circuit, to generate an output voltage.