The invention relates to a non-plug-in shaft torque measuring device which is formed by the combination of two semicircular main measuring arms, two auxiliary measuring arms, two main conducting rings, two auxiliary conducting rings and four pressure rings. Two ends of a measuring disc are affixed to the outer surfaces at the joints of the inner edges inside the two main measuring arms, and the measuring disc is affixed on a strain disc. The measuring device has the advantages of simple structure and convenient installation. Because of the semicircular structure of each component, the non-plug-in measurement of a shaft torque can be realized without disconnecting the installation structure of a measured shaft and changing the installation state of a measured system, and the accuracy of the measurement can be improved. The structure is compact after the components are installed, and the annular symmetric system has little effect on the quality eccentricity of the measured shaft, thereby similarly improving the accuracy of the measurement. The strain disc is affixed to the measuring disc to perform the measurement, only one resistance strain disc is needed to realize the measurementand can be used repeatedly, thus the cost is reduced.