A power adaptation circuit for outputting a power state signal, which includes three switch elements, a diode, three resistors and a capacitor, wherein each switch element includes a first terminal, a second terminal and a At the third end, a system power supply is grounded sequentially through the first resistor and capacitor, the first end of the first switching element is connected to the node between the first resistor and the capacitor, and is also connected to the anode of the diode, and the second end is connected to the second end through the first The two resistors are connected to a backup power supply, and are also connected to the first terminal of the second switching element, the third terminal is grounded, the second terminal of the second switching element is grounded, and the third terminal is connected to the system power supply through the third resistor, and serves as the The output end of the power adaptation circuit, the third end of the third switch element is used to receive a power-on signal, the second end is grounded, and the third end is connected to the cathode of the diode. The above power adapter circuit can effectively solve the problem of incompatibility between the computer motherboard and the power supply.