The invention relates to an anvil fixing device for a hinged cubic press, belonging to the technical field of superhard material synthesized equipment. The anvil fixing device comprises a steel ring (1) and a screw, wherein the inner holes of the steel ring (1) are an installing hole (3) of a press installing base, a cushion block installing hole (2) and an anvil installing hole (4); a part of a composite threaded hole (5) at the lower part of the steel ring (1) near to the inside of the steel ring (1) is a smooth round hole, and a part near to the outside of the steel ring (1) is provided with internal thread matched with the screw; an installing component (7) is installed in the smooth round hole; and one end of the installing component (7) near to the press installing base is a cambered surface matched with an external surface of the press installing base, or two intersectant planes forming a concave corner. The invention has good lateral support and bottom protection effects on the anvil, thereby improving the service life of the anvil, effectively improving the control accuracy of the press, reducing the error rate of the equipment, increasing the service life of the equipment, and reducing the work load of maintainers.