A charge gun controlled by a control circuit, comprising: at least one charging terminal (P1, P2, P3, PN) configured to be electrically coupled to an electric vehicle to charge the electric vehicle; a ground terminal electrically coupled to an equipment ground; a control pilot terminal configured to transmit a control pilot signal between the charge gun and the electric vehicle; and an over temperature detecting circuit electrically coupled between the ground terminal and the control pilot terminal, characterized in that: wherein the over temperature detecting circuit comprises a temperature sensor and a diode unit connected in series, and the temperature sensor is a temperature switch that is turned off when the temperature of the charge gun is lower than the safety limit value, and is turned on when the temperature of the charge gun exceeds the safety limit value, and when the temperature of the charge gun exceeds the safety limit value, the temperature sensor is turned on and the diode unit is in a forward period during a positive voltage level of the control pilot signal to control the positive voltage level of the control pilot signal to be switched from a first voltage level to a second voltage level different from the first voltage level, and when the positive voltage level of the control pilot signal is at the second voltage level, the control circuit is configured to perform over temperature protections according to the control pilot signal. at least one charging terminal (P1, P2, P3, PN) configured to be electrically coupled to an electric vehicle to charge the electric vehicle; a ground terminal electrically coupled to an equipment ground; a control pilot terminal configured to transmit a control pilot signal between the charge gun and the electric vehicle; and an over temperature detecting circuit electrically coupled between the ground terminal and the control pilot terminal, characterized in that: wherein the over temperature detecting circuit comprises a temperature sensor and a diode unit connected in series, and the temperature sensor is a temperature switch that is turned off when the temperature of the charge gun is lower than the safety limit value, and is turned on when the temperature of the charge gun exceeds the safety limit value, and when the temperature of the charge gun exceeds the safety limit value, the temperature sensor is turned on and the diode unit is in a forward period during a positive voltage level of the control pilot signal to control the positive voltage level of the control pilot signal to be switched from a first voltage level to a second voltage level different from the first voltage level, and when the positive voltage level of the control pilot signal is at the second voltage level, the control circuit is configured to perform over temperature protections according to the control pilot signal. wherein the over temperature detecting circuit comprises a temperature sensor and a diode unit connected in series, and the temperature sensor is a temperature switch that is turned off when the temperature of the charge gun is lower than the safety limit value, and is turned on when the temperature of the charge gun exceeds the safety limit value, and when the temperature of the charge gun exceeds the safety limit value, the temperature sensor is turned on and the diode unit is in a forward period during a positive voltage level of the control pilot signal to control the positive voltage level of the control pilot signal to be switched from a first voltage level to a second voltage level different from the first voltage level, and when the positive voltage level of the control pilot signal is at the second voltage level, the control circuit is configured to perform over temperature protections according to the control pilot signal.