A new model of branch point distribution of copolymer regarding molecular weight was postulated from the speciality of monovinyl-divinyl radical copolymerization. The effects of the model of branch point distribution and the index c in the relation [η]0

b /[η]0

1=g0c on the structure characterization of polymer with long-chain branches was discussed with the GPC-intrinsic viscosity method. A model of average branch density of copolymer before gel point was derived from vinyl chloride-divinyl suspension polymerization.The results of experiment were fitted with the models of average branch density and molecular weight before gel point

and it was found that the models fitted very well with the results of experiment with the new model of branch point distribution and C=0.72.It was concluded that the pendent double bond reactivity reduced by an order

and the crosslinking reaction was controlled by disffusion.At last

the correlation of intrinsic viscosity with viscosity average molecular weight was formulated well with [η]=0.2357M0.527v.