This utility model proposes a fully automatic sensor faucet, including a faucet housing. A detachable spout is installed inside the front end of the faucet housing, and a detachable sensor housing is installed at the front end of the spout. The sensor housing has a circuit board mounting slot with an opening at the top in the middle. A circuit board bracket is installed inside the mounting slot, and a circuit board is mounted on the bracket. A forward-facing sensor and a downward-facing sensor are electrically connected to the circuit board. The circuit board is covered by a shielding cover. A raised water-blocking ring is fixed to the bottom of the sensor housing, surrounding the downward-facing sensor. The water-blocking ring reduces the risk of the sensor housing accidentally triggering the downward-facing sensor due to water accumulation. This utility model features easy disassembly and installation of the spout and sensor housing, and simple maintenance. The water-blocking ring reduces the risk of the sensor housing accidentally triggering the downward-facing sensor due to water accumulation, resulting in better reliability. The use of dual sensors makes it suitable for different scenarios and offers better reliability than traditional single-sensor systems.