Abstract: Based on the experiments of the emulsion polymerization for the octamethylcyclotetrasiloxane (D₄), the physical concepts are introduced in the equation to substitute the polynomial of Bernstein in the Euclid space after analyzing the inherent law of discrete relative variables so that the approximate processes can be simplified and a mathematical model according to the wide range of the experiments has been put forward for the polymerization of D₄ in the following equation:   The processes of D₄ emulsion polymerization can be described with the model above.