Abstract: Elaborated in the paper are the study of the process parameters as made with the experimental pipe mill for hot-rolling of the S32750 super duplex stainless steel pipe,and the trial production activities as carried out with the large-sized hot-rolling mandrel mill with the optimized process parameters. It is proved by the practice that the existing hot-rolling mandrel mill is capable of producing the duplex stainless steel pipe,provided that the temperature for heating the billet is optimized,and the deformation amount is properly distributed. Employment of the said hot-rolling process to make the duplex stainless steel pipe will not only bring about high yield,but also cover the shortage of the extrusion process for making large-sized,extra-long steel pipe.