Abstract: The temperature field, the equivalent plastic strain field, the highest temperature and the cooling problem of INCONEL718 superalloy in radial forging were studied with Forge simulation software. In the first pass, temperature rising is focused on the surface to the half radial distance area. After the second pass, the billet core is the highest temperature area, and the temperature becomes more uniform than before, even if 45℃ higher than the initial. The highest temperature of the billet during radial forging rises firstly and then falls slightly. Thermal radiation is the main cooling mode in all of the cooling methods. The simulation result of equivalent plastic strain indicates that the billet has been forged through after the second pass. At last, a comparison with sample observations shows that the simulation results are reliable.