The analytical expression of the relationship between interference fringe spacing of target pattern and light time distribution of optical target reflection was derived by using the related knowledge of physical optics, Collins diffraction integral formula and the hard edge aperture complex Gauss function decomposition method. The quantitative relationship between interference field fringe spacing, optical aperture size and target reflected light time distribution of envelope peak number, peak to peak spacing and peak to peak ratio was discussed from the aspect of principle analysis, simulation and experimental. The results show that when the fringe spacing is about the size of the target aperture, the peak number of reflected light time distribution envelope is from single peak to multi peaks, and the peak to peak spacing and peak to peak ratio curves appear a maximum value. The estimation results of the aperture parameters can be deduced according to the change rule of parameters mentioned above, its accuracy is affected by the fringe spacing adjustable range.