The process of gas cylinder necking by hot spinning was simulated using the finite element analysis software MSC.Marc, and the variation of wall thickness of tubular workpieces, equivalent strain rate, stress and spinning force in temperature and feed rate were analyzed. The results show that the radial spinning force is very close to the total spinning force results in the tubular workpiece circumferentially compressed and different levels of decrease and increase in wall thickness occurred at different areas. As the spinning temperature and the roller feed rate increase, the unit wall thickness grows thinner at the spinning starting point of the tubular workpiece and thicker at the cylindrical shell and the shoulder part. Proper selection of the feed rate can effectively control the wall thickness changes.