A power supply circuit for an infrared cut removable (ICR) filter includes an identifying module, a supply mode module, a switching module, and a power source module. The identifying module generates a first identifying signal when the brightness of external light is higher than a preset brightness; otherwise, the identifying module generates a second identifying signal. The supply mode module generates a power supply corresponding to the power supply mode of the ICR filter. The switching module includes two connecting nodes for connecting to the ICR filter and loads the power supply generated by the supply mode module on one of the nodes correspondingly according to the first and second identifying signals. The power source module is connected to an external DC power supply and generates an operating voltage for the identifying module, the supply mode module, and the switching module.