As a branch of quantum information technology, ghost imaging comes to front for its unique “ghost” feature, i.e. the image would appear on the optical path that actually never pass the object. For a time, entanglement was thought to be a prerequisite, while we know now that classical thermal light can imitate this kind of imaging and there is no need for entangled beams. Based on the theory of statistical optics, we modeled the dynamic process of thermal variation, the propagation of optical fields and the optical modulation by objects, and then retrieved the Fourier transform patterns of both an amplitude-only object and a pure phase object. The latter experimental results demonstrate the accordance of numerical prediction based on statistical optics.