PVC─SR was prepared from the reaction of PVC and sodium N, N-di-ethyldithiocarbamate. Products of self-crosslinked PVC─SR and co─crosslinked PVC─SR/NBR blend were obtained under heating. Effects of temperature and weight of sodium N,N-diethyldithiocarbamate on substitution reaction and degree of functionality of PVC─SR on the gel content, tensile properties and compress set of crosslinked products were investigated. Mechanism of crosslinking reaction was discussed.