The present application provides a control circuit of a switching power supply, the control circuit comprising: a central control circuit which has a first control port, a second control port, and a third control port; and a current selection circuit which is disposed between the third control port and a ground and has two or more selection terminals, a connection state between the selection terminals being switched between different connection states to adjust the output current value of the switching power supply, wherein the different connection states include disconnection, shorting, and connection with a resistor having a predetermined resistance value. According to the present application, the output current value of the switching power supply is adjusted by switching the connection state between the selection terminals between the states of disconnection, shorting, and connection with a resistor having a predetermined resistance value.