The utility model discloses a temperature sensor fixing device that steam turbine thermal test used, including the mounting and the piece that keeps warm, the mounting include the base of semicircle arcuation and the cutting ferrule of semicircle arcuation, cutting ferrule and the upper and lower setting of base, both form the hole that supplies temperature sensor temperature sleeve pipe to pass, the one end of cutting ferrule links to each other through axle and base, cutting ferrule and base can be along the rotation of axes, the other end of cutting ferrule passes through buckle and base cooperation, realizes fixing temperature sensor, the piece that keeps warm sets up the clearance of cover between temperature sensor upper seal temperature sensor and temperature sleeve pipe, it includes a conical support, follows its central line and set up a through -hole inside the toper support, and respectively be provided with the cylindrical section at the both ends of toper support, the mounting and the adoption rope connection between the piece that keeps warm.