Abstract: The influence of the scattering was researched from three aspects about the width and thickness of steel plate and ray energy. The simplified Monte-Carlo model of the crown measurement was built, and the influence of the width and thickness of the plate on the distribution of scattering factor was analyzed. The X-ray spectrum simulation model was established, based on which the X-ray continuous energy spectrum under a given tube voltage was simulated. And then an equivalent method was put forward to use multiple single energy to replace the actual continuous spectrum during the calculation of the scattering distribution rule in practice. In the contrast, the simulation results can well accord with the experimental measurement results.