The invention belongs to the technical field of measuring of the permeability of a rock mass, and discloses a variable pressure adjustable rock mass fracture permeability testing device. The variablepressure adjustable rock mass fracture permeability testing device comprises plugging devices, a converter, a communicating pipe, a drilling machine, a drill pipe and a control operation platform. Theconverter is in threaded connection to the tail part of the front plugging device and internally comprises an inner ring, a spring and a cross-shaped screw sleeve, the compression degree of the spring is changed by regulating the cross-shaped screw sleeve, and the starting pressure of the inner ring is further controlled; the front plugging device and the tail plugging device form a water injection cavity with a drilling hole after being expanded, and the external high pressure water enters the water injection cavity through the converter to detect the fracture permeability of the drilling hole. The testing device simplifies the external operation system and the operation step, the number of pipelines in the drilling hole is reduced to one, the problem of wire winding of the drill pipe isavoided, the stability of the measurement process is improved, the plugging process and the measuring process respectively work at the respective pressures by using a same water source, and the variable pressure of the converter is adjusted to adapt to different working environments and the starting pressure requirements.