Abstract: ¹H-NMR technique was used to study systematically the additive products formed by the hydrosilation reactions of the unsaturated ester. The chemical shifts of ¹H-NMR spectra of the additive products were assigned. We advanced the method to calculate the percentage of the α-and β-species in the additive products. In contrast with chemical analysis method, the advantages of this method are rapid accurate and capalle to follow the changes of the structure of the reaction system.