The invention discloses a hydraulic torque converter and mainly relates to the field of oil and gas well drilling. The hydraulic torque converter is installed between a bottom drilling tool combination and a drill column. The hydraulic torque converter is mainly composed of a center shaft, an outer shell, bearing devices, an adjustor, a spring, a hydraulic clutch, a coupler, a torque generator and a nozzle. Due to the special structure and the special connecting function relation among the center shaft, the outer shell, the bearing devices, the adjustor, the spring, the hydraulic clutch, the coupler, the torque generator and the nozzle, the hydraulic torque converter can achieve drill column rotation on the premise that reactive torque of the bottom drilling tool combination is balanced and a tool face is stabilized and can also complete tool face adjustment or composite rotation well drilling work. The drilling speed of a well of a complex structure can be better increased, the well track control precision can be better improved, in addition, a conventional sliding well drilling manner can be changed into a rotation well drilling manner, sliding friction resistance of the drill column is effectively reduced, and the hydraulic torque converter is of great significance in improving the well drilling efficiency of the well of the complex structure. Meanwhile, the hydraulic torque converter has the beneficial effects of being simple in structure, convenient to operate and install, safe and reliable.