To overcome the shortcoming of traditional ground-based methods of which the observation is limited, the method of inverting aerosol optical depth (AOD) by remote sensing image is gradually emerging. Compared with the traditional inversion methods, the Simplified Aerosol Retrieval Algorithm (SARA) is more universal. To further improve the accuracy, a nonlinear optimization method which uses multi-parameters to invert aerosol from Moderate-resolution Imaging Spectroradiometer (MODIS) is proposed. By treating the aerosol optical depth inverted by SARA as the initial value, the method optimizes the optical thickness, single scattering albedo (ω), asymmetry factor (g) and surface reflectance fitting parameter (ρ′s=k*ρs+b) simultaneously, so as to obtain the optimal solution. The results show that under the same conditions, the nonlinear optimization method is obviously superior to the SARA. The correlation coefficient of the nonlinear optimization method for single point precision verification is 0.8118, which is better than the 0.2624 of SARA. Compared with the inversion values from MODIS aerosol product (MOD04), for the case of July 6, the correlation coefficient of the nonlinear optimization method is 0.7612, which is better than 0.5916 of SARA. For the case of May 3, the correlation coefficient of nonlinear optimization method is 0.9036, which is better than 0.8788 of SARA.