Abstract: The hi-pressure steel tubular product has to be satisfactory to relevant very stringent requirements for internal surface quality and I.D.tolerance.The influence of the type of process tools on the manufacture of the tube is investigated.Based on the result,a new type mandrel is developed.With the MSC.MARC FE simulation software,the drawing process of the hi-precision tube is simulated,and the law of the influence of the said mandrel on the geometric tolerances of the tube is analyzed,which are considerable helpful to the research and production of the hi-precision tube.