The invention relates to an insulating and heating riser forming device which comprises a pot body, a slurry stirring device, a riser die, a die turning device, a pneumatic hollow speed reducer, a vacuum sedimentation tank, an idler wheel and an idler wheel adjusting device. An exhaust hole of the riser die is hermetically and fixedly connected with a hollow output shaft of a pneumatic hollow speed-reducing motor, a turning arm of the die turning device is fixed on the outer shell of the pneumatic hollow speed-reducing motor, and an air inlet of the vacuum sedimentation tank is connected witha central hole of the pneumatic hollow speed reducer through a hose so that the air inlet of the vacuum sedimentation tank is communicated with the exhaust hole of the riser die. The forming device of the invention can be utilized to realize the automated production of forming risers so as to greatly improve the manufacture efficiency of the risers and lighten the labor intensity of a staff. The produced risers have the advantages of constant appearance, improved yield, even density and good insulation effect, therefore, the qualities of the risers are greatly improved; and the production cost is decreased by adopting automated production.