Abstract: The effects of additives and fillers including processing aids, impact modifiers, lubricants and metal soaps on rheology of poly(vinyl chloride) have been investigated through analyzing the processing rheological curves of rigid PVC. The experimental results showed that the processing aids acrylic resin(ACR) and inner lubricant could promote the fusion of RPVC, but external lubricant prolongs fusion time. Chlorinated polyethylene(CPE) as impact modifiers has less effect on RPVC fusion time. The fusion time would be shortened with increase of content of inner lubricant metal soap, but prolonged with increase of content of exrernal lubricant metal soap.