The invention discloses an LED power supply with no-load and light-load protection output and capable of receiving phase-cut dimming stably, which comprises a balancing resistor, a high-voltage dimming signal detecting circuit, a capacitor array with controlled volume, a system power supply, a low-voltage dimming signal detecting circuit, a voltage-PWM conversion circuit, an output overvoltage and undervoltage protection circuit, a voltage or PMW dimming constant-current source, and a capacitor array output control circuit, wherein the capacitor array with the controlled volume is controlled by the capacitor array output control circuit to match the balancing resistor consisting of NTC thermistors, so that the power of the power supply forms a certain direct proportion relation with filtering capacitance; a phase-cut dimmer is in a good phase-cut state, and a dimming signal is generated by the dimming signal detecting circuits to control an LED constant-current source so as to realize the LED dimming of the LED power supply; and the overvoltage and undervoltage protection circuit is set at the output of a constant-current power supply, so that LED hot plug and no-load and light-load protection are realized. Therefore, the LED power supply has great application prospects in the aspect of LED dimming.