In order to ensure the dimensional accuracy and control the thinning rate of the large diameter support rod of heavy rocket engine frame, the forming process simulation and research were carried out. The tube was necked by return spinning, and ABAQUS was used to simulate the effect of different feed rate on the necking spinning. DC-1600CNC spinning equipment combined with self-designed spinning wheel and clamping device was used for process test, and the process parameters such as spinning speed, spinning pass and single pass reduction were optimized through the test. The results show that the method can successfully obtain qualified parts, ensure that the pressure angle deviation is -1° and the symmetry deviation is 0.3 mm, the wall thickness range is 7.3-7.6 mm, and there is no obvious wrinkle in the spinning area.