The invention provides a hydraulic bending machine. The hydraulic bending machine comprises a bending machine body. The bending machine body comprises an upper die base, an upper die, a lower die base, a lower die and a throat. The upper die is fixed below the upper die base, and the lower die is fixed above the lower die base. The upper die and the lower die are correspondingly arranged. The throat is vertically arranged on the front face of the lower die, so that parts to be machined are bent. The throat is of a groove structure, and the bottom of the groove structure is arranged to be in a smooth arc shape. The up-down radial length of a groove is 25-30cm, and the throat depth is 10-20cm. A workpiece positioning device is arranged at one end of the throat. The workpiece positioning device is fixed to the position 3-8cm away from the surface of the throat. According to the hydraulic bending machine, the fixed positions can be adjusted in the axial direction and the radial direction at the same time on the whole; and moreover, the adjusting structure is simple in arrangement, adjusting is flexible and the adjusting position is accurate. In addition, the workpiece position adjusting device is arranged, fixation is further performed, the steps and time used for positioning from the beginning are omitted, the bending efficiency can be effectively improved, and the positioning effect and bending effect are guaranteed.