Polyfunctional monomers (PFM) were important sensitizers for radiation crosslinking applications. It is supposed that free radicals formed initially on the main chains of the irradiated polymer initiate grafting polymerization of the double bonds in the PFM molecules and form the grafted special chains which crosslinked together the polymer’s main chains. Based on this simplified sensitized crosslinking model and other necessary assumptions, an expression correlates crosslinking density (,q,), absorbed dose (,D,) and PFM content (,C,0,) was derived. Analyzing results of published data demonstrated that ,q, values of polyethylene-co-propylene (EPR), polyisoprene (IR), polychloroprene (CR) and polystyrene-co-butadiene (SBR) increase linearly with ,D, and ,C,0, and the ,q, of IR increases linearly with ,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=41914811&type=,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=41914813&type=,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=41914812&type=, .