Based on the split-step-Fourier-transform and the diffraction theory of hot-image model we made the simulation of the evolvement of hot-image in case of thick nonlinear medium. The changes of some parameters influencing the intensity and location of hot-image, such as the modulation coefficient (including amplitude modulation and phase modulation), the distance between scatterer and the front surface of nonlinear medium, the size of the scatterer, the intensity of incident beams and so on, were detailedly analysed respectively. Numerical results were found to be in agreement with analytical theory for the changes in modulation coefficient and the intensity of incident beams, but not in agreement with analytical theory for the changes in the size of the scatterer. Moreover, when the distance between scatterer and the front surface of nonlinear medium is zero, hot-image will also be found on the back surface of nonlinear medium.