The uniform design method is used to arrange experiment of dispersion polymerization of styrene, butyl acrylate and acryl acid. The stepwise regression technique is adopted to analyze the results. The mathematical models are built by regression equations between the microsphere conversion rate, the size and its distribution. There are many influencing factors, such as, 3 monomer concentrations, stabilizer concentration, initiator concentration, ratio of alcohol and water, temperature established, and their reliabilities evaluated. Although the predicted values from regression equation different from the observed values (relative divergences less than 10%)，the regression equation can be used for designing particles and mechanism research. All above researches can be used for optimizing dispersion polymerization reaction conditions.