Abstract: This paper considers pendant double bond as the third double bond in monoene/diene radical crosslinking copolymerization (RCC),and the model can be simplified when the amount of divinyl monomer is less than 5%(mol).Free radical tri-polymerization is introduced instead of free radical crosslinking copolymerization.For MMA/EGDMA free radical crosslinking copolymerization,since the vinyl structure of the MMA and EGDMA is identical,the model is simplified further by considering the vinyls of MMA,EGDMA and pendant double bond have equal chemical reaction ability.An empirical function developed by W.H.Ray is used to describe auto-acceleration phenomena,and diffusion effects should show additional crosslinking influence at this time.Then a coefficient k which comes from Arrhenius activation energy concept was introduced to amend reaction speed parameter,which involves termination reaction and crosslinking reaction,so the effect of crosslinking joint on RCC could be described.Finally,a statistics-kinetic model is established.The relationships between conversion and copolymertization time,average crosslink density with conversion are investigated.The curves predicted by the model fit well with experimental data.