The invention relates to a centrifugal compressor torque monitoring device, and relates to the technical field of structural design of centrifugal compressor safety maintaining machines. The device isused for monitoring torque changes of a rotor of a centrifugal compressor, a torque indexing disc is arranged at the positions, close to the two ends of a spindle, of the spindle in a sleeving manner, grooves are formed in the circumferential direction of the torque indexing disc in an equal-angle spaced manner, a phase probe and the torque indexing disc are arranged on a machine shell in a matching manner, the phase probe is used for detecting torque changes of the torque indexing disc and generating first signals, a toque analysis device is electrically connected with the phase probe, usedfor receiving and calculating and analyzing a first signal, obtaining torque and the rotating sped of the rotor of the centrifugal compressor and obtaining power of the centrifugal compressor according to the torque and the rotating speed. Through power changes, responsibility equipment with the torque change is obtained, it can be distinguished that the power is changed due to the drive device failure or the failure of a certain compressor, and accurate data information is provided for maintaining of the responsibility equipment by a decision maker at the first time.