The propagation properties of the soliton in the photorefractive crystal under Compton scattering were studied by using the model of multi-photon nonlinear Compton scattering and nonlinear Schr?dinger’s equation. The result shows that the essence of the heat-lens effect in the photorefractive crystal is a result of the propagation and coupling of the crystal soliton and space charge field soliton. The coupling properties have the relation with not only the relative phase of the solitons in the two wave guides, but also Compton scattering. When the relative phase of the soliton is same or opposite, the energy change and its cycle change between the two solitons taken place by Compton scattering. Therefore, the overall of the soliton formed by Compton scattering is fuzzy. If the soliton propagation is along with the optic axis direction, then, the birefraction induced by Compton scattering is possible.