The invention relates to a torque calibration test bed for a loader transmission shaft. The test bed mainly comprises a power module, a speed reducing module, a torque sensor, a switching module and an end part supporting module, wherein a motor in the power module is connected with a speed reducer in the speed reducing module through a shaft coupling; the speed reducer realizes gear transmission with a central shaft through a pinion and a large toothed sector; the central shaft is arranged on a bearing seat bracket through a bearing and a bearing seat; the torque sensor is coaxially fixed between the central shaft and a left deformed ring flange in the switching module through a flange; and a right deformed ring flange of the switching module is connected with a slipway of the end part supporting module in a sliding way through a slide block on a right deformed ring flange bracket. The limit of manual torque loading is overcome, the test bed is suitable for calibrating torques of loader transmission shafts of different specifications and different lengths, and quick calibration of the torques of different types of loader transmission shafts is realized.