The invention discloses a monitoring device for a true triaxial test. The device comprises an acoustic emission monitoring component and a temperature monitoring component, wherein the acoustic emission monitoring component comprises an acoustic wave probe and an acoustic emitter, the acoustic wave probe is embedded in the groove at the surface of the test piece, and the signal line of the acoustic wave probe is connected from the true triaxial loading component to the acoustic emitter; the temperature monitoring component comprises a temperature probe and signal acquisition equipment, the temperature probe is inserted into a mounting blind hole at the surface of the test piece, the mounting blind hole is internally provided with a mounting joint correspondingly matched to the temperatureprobe, and the cable of the temperature probe is introduced from the true triaxial loading component to be connected to the signal acquisition equipment. The monitoring device can effectively avoid the interference of the externally irrelevant signals, ensure the monitoring precision of the acoustic wave probe and the temperature probe, and make the acquired data more realistic and accurate.