The invention belongs to the technical field of asphalt mixture shear behavior testing, and relates to a testing device of the pressure-torsion shear failure performance of an asphalt mixture. The device provides a constant-temperature environment through an outer circulating heat preservation system and exerts axial pressure and torsion loads on asphalt mixture test pieces in an independent or combination mode. A dual-layer plane ball bearing is arranged, transmits axial pressure to a left fixed plate and releases torsion loads; a square-section section is arranged at the right end of an axial pressure loading shaft, and torsion loads are borne by a square hole of a right fixed plate; a spring is arranged to buffer axial pressure loads. A torque sensor and a pressure sensor which are completely separated spatially are adopted, the measuring ranges of the two sensors do not need to be matched, and the two sensors do not influence each other. By means of the device, the failure process of the asphalt mixture in the moderate and high temperature environment and the complicated torsion stress state can be simulated; when the torsion loads continuously change, the direction of the main stress axis of a test piece continuously changes, and the change characteristic of the real stress state of a road surface is met.