In-line holography (holography of Gabor) is a simple and effective method of holographic investigation of the structure of objects. The computer simulation of holographic images is based on the numerical solution of Fresnel integrals with fast Fourier transform algorithms. We propose a new method for the numerical reconstruction of holographic image. This new method is based on two-step propagation. The two-step propagation method is described for the case of a fixed and relatively arbitrary choice of the sampling grid in the object and observation planes. There are have many ways to computer simulation of two-step propagation. In this paper simulate based on convolution signal with a transfer function of impulse response.