The simulation of GH4169 thin\|walled tube ball\|spinning process was carried out by the finite element software of Deform-3D to reveal the reason of defects of the thin\|walled tube. The affection rule of surface ripple, port bellmouth and diametral growth defects were analyzed under the different technical parameters. Experiments were also performed to verify the validity of the simulation results. The results show that when feeding ratio in the range of 0.8~1 mm·r^-1, spindle speed of 180 r·min^-1 and reducing rate of 30%, the surface quality of pipe is better with smaller diametral growth and steady spinning process.