An induction faucet which comprises: a faucet, which has a contactless automatic switch mode and a manual switch mode with contacting a mechanical handle; a sensor, which is arranged on the faucet; a solenoid valve, which is arranged on a water outlet path of the faucet, and is connected with the sensor, wherein when the sensor and the solenoid valve are in a working state, the faucet supplies water by the automatic switch mode; a switch, the switch being configured to switch the faucet from the automatic switch mode to the manual switch mode when the sensor and/or the solenoid valve are detected not to be in the working state; a power supply, which is respectively electrically connected to the sensor and the solenoid valve; a control circuit board, which is connected to the power supply; a control program, which is respectively connected with the control circuit board, the solenoid valve and the sensor, and is configured to determine whether the solenoid valve and/or the sensor are in the working state by detecting whether a sufficient voltage is supplied for the solenoid valve and/or the sensor by the power supply, wherein when the voltage is detected to be lower than a preset voltage threshold, the control program controls the switch to switch the on-off state of the liquid flow conduit to the working mode controlled by a mechanical valve; an indicator light, which is connected with the control program, and is configured to flash when a voltage supplied from the power supply detected by the control program is insufficient to maintain the working state of the solenoid valve and/or the sensor; wherein the control program adopts a three-stage mode for detecting the voltage, wherein the first stage is that a battery supplies a normal working voltage when the voltage of the battery is 4.7-6 V, the second stage is that the battery supplies an insufficient voltage when the voltage of the battery is 4.5-4.7 V, the indicator light being in a prompting mode by slowly flashing red light, and the third stage is that the battery is dead when the voltage of the battery is below 4.5V, the indicator light being in a prompting mode by quickly flashing red light. a faucet, which has a contactless automatic switch mode and a manual switch mode with contacting a mechanical handle; a sensor, which is arranged on the faucet; a solenoid valve, which is arranged on a water outlet path of the faucet, and is connected with the sensor, wherein when the sensor and the solenoid valve are in a working state, the faucet supplies water by the automatic switch mode; a switch, the switch being configured to switch the faucet from the automatic switch mode to the manual switch mode when the sensor and/or the solenoid valve are detected not to be in the working state; a power supply, which is respectively electrically connected to the sensor and the solenoid valve; a control circuit board, which is connected to the power supply; a control program, which is respectively connected with the control circuit board, the solenoid valve and the sensor, and is configured to determine whether the solenoid valve and/or the sensor are in the working state by detecting whether a sufficient voltage is supplied for the solenoid valve and/or the sensor by the power supply, wherein when the voltage is detected to be lower than a preset voltage threshold, the control program controls the switch to switch the on-off state of the liquid flow conduit to the working mode controlled by a mechanical valve; an indicator light, which is connected with the control program, and is configured to flash when a voltage supplied from the power supply detected by the control program is insufficient to maintain the working state of the solenoid valve and/or the sensor; wherein the control program adopts a three-stage mode for detecting the voltage, wherein the first stage is that a battery supplies a normal working voltage when the voltage of the battery is 4.7-6 V, the second stage is that the battery supplies an insufficient voltage when the voltage of the battery is 4.5-4.7 V, the indicator light being in a prompting mode by slowly flashing red light, and the third stage is that the battery is dead when the voltage of the battery is below 4.5V, the indicator light being in a prompting mode by quickly flashing red light.