The invention discloses a surface temperature sensor, comprising a housing (1); the outside of the housing (1) is a step-shaped structure which becomes smaller from the middle to left and right ends; the outside of a right end step column of the housing (1) is sleeved by a magnet ring cover (3); a magnet ring (2) is embedded in the magnet ring cover (3); the central section of the magnet ring (2) sleeves the right end step column of the housing (1). The central section of the housing (1) is provided with a through hole penetrating from left to right; the through holes is successively in connection with a temperature control switch (4), a lead (5) and a four-core aviation plug (6) from right to left; the outside of a left end step column of the housing (1) is provided with a segment of external threads. The surface temperature sensor is provided with the external threads, the magnet ring and the magnet ring cover; components employs interference fit; the surface temperature sensor has a simple structure, is convenient to disassemble and assemble, has sensitive response, and can greatly improve work efficiency and reduce working strength.