Abstract: The effect of rare-earth element Ce on the hot deformation behavior of as-cast 00Cr25Ni7Mo4N super duplex stainless steel (SDSS),which was carried out on Gleeble-3800 hot simulator in temperature range of 1 100,1 150,1 200 ℃ and at a stain rate of 5 s-1,was investigated by using optical microscope,scanning electron microscope,and X-ray energy dispersive spectrometer etc.The results show that Ce could reduce the oxygen and sulfur contents,and the inclusion transformed from sulfide inclusion to rare earth inclusion,thus to some extent improve the hot deformation capacity of the as-cast SDSS .The proper amount of Ce was between 0.165% and 0220%.The optimizing temperature range of hot deformation was 1 150-1 200 ℃.