Crosslinking is an effective way to improve the qualities of poly(vinyl chloride). A crosslinking system consisting of R-glycidoxypropyltrimethoxysilane (KH560) has been first used to introduce crosslinking into rigid poly(vinyl chloride). Different thermal stabilizers (organotin, Ca/Zn stearate, and Ba/Zn stearate) as well as sodium bisulfite additive were tried to promote the grafting of epoxyl group and enhance the degree of crosslinking. FTIR spectra showed that grafting and crosslinking of KH560 with poly(vinyl chloride) could take place, and a gel content of 40% could be obtained when more than 10 phr epoxylsilanes were used in the condition of 2 : 1 (parts by weight) ratio of BaSt(2)/ZnSt(2) and 1 : 1M ratio of NaHSO3/ KH560, while the premature crosslinking was avoided. Thermal properties had been studied. The results showed that the Vicat softening temperature of crosslinked PVC could be improved about 10 degrees C when 5 phr epoxylsilane was added, and thermal degradation could be delayed with increase in gel content. Therefore, epoxylsilane-crosslinked PVC will have the potential for extensive applications.