The hydrosilylation of polyhydrosiloxane and unsaturated allylic polyether terminated with ester group is processed with chloroplatinic acid as catalyst and ethyl acetate as solvent to exclude the mass transfer resistance in the system. The kinetic study is performed by means of Gel Permeation Chromatography. Within the experimental range (mass ratio of the whole reactants to solvent is 1:4, the mol ratio of Si-H. bond to carbon-carbon double bond is 1:1.3, the catalyst concentration from 1.0 X 10(-4)mol(.)L(-1) (Pt) to 3.1 X 10(-4) mol(.)L(-1) (Pt), temperature between 338.15K and 350.35K), a kinetic model of zero-th order reaction is built up and the evaluated model parameters are found to change linearly with the catalyst concentration.