The invention discloses a three-state variable-frequency LED (light emitting diode) power supply output power control circuit, which comprises a variable-frequency control module, wherein the variable-frequency control module is provided with a variable-frequency control end positive LED+, a variable-frequency control end negative electrode LED- and a lamp turning-on control signal input end LDRV and high brightness control signal input end MDRV; the variable-frequency control end positive electrode LED+ is used for electrically connecting an IC chip U1 in a variable-frequency LED driving power supply; the lamp turning-on control signal input end LDRV and the high brightness control signal input end MDRV are used for connecting an external central control unit; the variable-frequency control module comprises a PWM (pulse width modulation) generating circuit, a variable-frequency driving circuit and a photoelectric coupler; the PWM generating circuit changes the duty ratio of an output PWM signal according to the lamp turning-on control signal and the high brightness control signal input by the external central control unit; the output power of the variable-frequency LED driving power supply is regulated so that the LED load performs low-power and low-brightness operation or high-power high-brightness operation; the soft starting with the gradually changed lamp light can be realized. The three-state variable-frequency LED power supply output power control circuit has the advantages that the electronic devices are few; the circuit structure is simple; the production cost is low; the power consumption is low, and the like.