(3,4-Difuryl-2,5-dimethyl)phenyl-polyvinyl silicon oils (DDP-C-gum) were synthesized by Diels-Alder reaction of polyvinyl silicon oil (C-gum) with 3,4-difuryl-2,5-dimethylcyclopentadienone (DDCP) in diphenyl ether at reflux temperature under atmospheric pressure. Their structures were characterized by H-1-NMR, UV, and IR spectra. Properties such as viscosity, refractive index, color, and thermal stability of some DDP-C-gums were obtained.