Monte Carlo method is enhanced to simulate single-, two-photon excitation fluorescence microscopic imaging through turbid media Furthermore, a rapid modeling method, which is based on point spread function, is developed to study lateral resolution. Since simulation of scanning process in imaging is avoided, high efficiency is obtained. With this model, effects of numerical aperture (NA) on single- and two-photon microscopic imaging through turbid media are researched. Results show that higher NA brings lower lateral resolution but higher axial sectioning ability.