Tacho-Torque measuring instruments are often used in the measurement of mechanical power of engines and other equipment. The measured technical parameters include torque, speed and power. Currently, the calibration of torque and speed measuring instruments mostly use the method of calibrating static torque and speed seprartely, which deviates greatly from the state of use. This paper introduces a torque / power standard device for multi-parameter synchronous calibration of a tacho-torque and power measuring devices. The overall mechanical structure, the design principle of standard torque generation system, the establishment of torque measurement model and the influence factors of measurement uncertainty are introduced. Through influencing factor analysis and experimental verification, it is concluded that the measurement uncertainty of the device’s recurrence value is less than 0. 2% . The device is used to calibrate various types of tacho-torque measuring instruments, and the results show that the device can achieve the function of applying the standard torque in the rotating state, and achieve the expected technical indicators, It can provide a technical means for the multi parameter synchronous traceability of this type of measuring instruments in the way close to the working state.