Machine tool spindle torque loading test system

The utility model discloses a machine tool spindle torque loading test system which is used for testing the reliability and the loading performance of a machine tool under a heavy-load working condition. The system comprises a supporting part, a testing part, a loading part and a transferring part. The supporting part comprises a torque sensor and an accessory thereof. The loading part comprises a magnetic powder brake and an accessory thereof. The transferring part comprises a connector, a speed reducing box and plum-blossom-shaped couplers. The speed changing box and the machine tool are connected through the connector. The speed changing box is arranged on a loader box body. Speed-changing-box-and-torque-sensor connecting and torque-sensor-and-magnetic-powder-brake connecting are carried out through the two plum-blossom-shaped couplers respectively. During machine tool operation, braking torque generated by the magnetic powder brake is used for carrying out torque loading on a machine tool spindle, and the torque sensor carries out real-time measuring.