Abstract: Presented here in the paper are the R & D of the large-sized seamless austenitic stainless steel tube,and some new ideas as applied in the developemnt activities,including the following technical measures:controlling the forging ratio within the range of 3.0-3.5 to produce properly-forged tube blanks;applying relevant professional 3D design softwares to simulate and calculate the parameters of the piercing process;enhancing the service span of the piercing plug via surface treatment and lubrication,and internal cooling;and designing and manufacturing the combined guide plate of the piercer to reduce costs of the operational tools for making large-sized stainless steel pipes.The finished pipes are tested for their chemical composition,mechanical prop-erties,grain size and intergranular corrosion resistance,etc.The test rersults demonstrate the full compliance of the pipes with the requirements as specified in ASME SA 312/SA 312M.