The invention discloses a hydraulic machine for prepressing and forming nuclear fuel. The hydraulic machine comprises a frame and a soft mold. The frame comprises an upper cross beam, two upright posts, four locking nuts, a lower cross beam, a fixed workbench, an upper pressure head and a lower pressure head, wherein the upper cross beam and the lower cross beam are arranged at the upper ends andlower ends of the upright posts correspondingly and are fixed by the locking nuts; the middle portions of the upright posts are provided with the fixed workbench; the upper pressure head is arranged on the upper cross beam; a hydraulic cylinder is arranged in the frame, and the lower pressure head is arranged on the upper end surface of a piston rod; and the upper pressure head and the lower pressure head are used for forming the nuclear fuel in the soft mold. The hydraulic machine for prepressing and forming the nuclear fuel can prepare the nuclear fuel through prepressing forming, solves theproblem that prepressing forming equipment for nuclear fuel elements in China was not available from scratch, provides a new equipment category, fills the market gap, and provides key industrial equipment for China's nuclear power plant system engineering.