In numerical simulation of image reconstruction from computer generated holograms, Fresnel diffraction integration using FFT is generally used in order to calculate propagation of light waves. There are disadvantage of impairing accuracy and flexibility in FFT. Therefore, we create simulator of image reconstruction based on point light source method of computer-generated holograms using Fourier Transform Optical System. It enables to calculate images with high accuracy and flexibility. By the experiments, we confirm the method simulates reconstruction process successfully.