A thermal protection circuit to protect an electronic device from over-heat comprises a temperature sensor, a hysteresis comparator and a switch circuit. The temperature sensor senses internal temperature of the electronic device and output an internal temperature signal with voltage. The hysteresis comparator outputs a power-off signal when the voltage of the internal temperature signal is lower than a low voltage threshold representing an a determined temperature, or outputs a power-on signal when the voltage of the internal temperature signal is higher than a high voltage threshold representing a restarting temperature. The switch circuit stops transmitting power signals to the electronic device in response to the power-off signal, or continues to transmit the power signals to the electronic device in response to the power-on signal.