Abstract: Comparing with the traditional mono-energy X-ray imaging inspection system, dual-energy X-ray transmission imaging system has the ability of simple object identification. It can automatically classify the materials into organic, inorganic and mixture signing with different colors. In order to enhance the object identification ability of dual-energy imaging system, HSB color model was applied in pseudo dual-energy X-ray transmission imaging system and the special method of color mapping was used for signing pixel colour in this paper. The experiments on 1/3 scale system show that the object identification ability is improved by using HSB color model.