The utility model relates to a steam quality measurement instrument, which comprises a steam temperature sensor (1), a thermal conducting rod (9), temperature sensors (8, 11), a radiator (7), a thermal-insulation sheath (12), an outer sheath (10), a target flowmeter (4) and a digital display meter (3). The thermal conducting rod (9) has a hot end and a cold end, and the hot-end temperature sensor (11) and the cold-end temperature sensor (8) are respectively embedded in the both ends; the wall surface at the cold end of the thermal conducting rod is fixedly connected with the bottom surface of the radiator; the hot end directly contacts with wet steam in a steam pipe (6); the thermal-insulation sheath is sheathed on the thermal conducting rod; and the outer sheath is sheathed on the thermal-insulation sheath. The outer sheath is fixed in holes on the wall of the steam pipe, the target flowmeter and the digital display meter are arranged on the steam pipe for collecting the temperatures and the fluid impact force of the steam temperature sensor, the hot-end temperature sensor and the cold-end temperature sensor, and the above data are processed to obtain the steam quality. The steam quality measurement instrument has the advantages of high measurement accuracy, stable and reliable operation, simple structure and low cost.