Abstract: Three key influencing factors of specific growth rate of microalgae, i.e. CO₂ concentration, light intensity and nitrogen concentration were chosen, and ten kinds of univariate non-linear models used to construct a multivariate non-linear model between the three factors and the specific growth rate of microalgae by constructional function method. After the correlation parameter test of the significance P value less than 0.05 and the collinear diagnosis of VIF less than 5, the final determination coefficient (R²) of the multivariate nonlinear regression equation was 0.917, which could be used for the effective prediction of the growth rate of microalgae. On this basis, through the analysis of the effect of the equation on the three factors, it was concluded that when CO₂ concentration was 5%-15%, the specific growth rate of microalgae was high, and the specific growth rate gradually increased with the increase of light intensity (45-480 μmol/(m² ·s)) and nitrogen concentration (0-700 mg/L). The biomass yield of microalgae was predicted to be 7.2-100.2 kg/(m³ ·a) by regression model, and the absorption and fixation of CO₂ by microalgae was estimated to be 7.92-183.70 kg/(m³·a).