Abstract: Chitosan/cellulose biomass foaming composites were successfully prepared by a freeze dry method using chitosan particles as reinforcement and ionic liquid as cellulose solvent. The microstructure, crystallization property and thermo-stability of porous composites were characterized by SEM, XRD and TGA, respectively. The porosity and water absorption ability were also analyzed. The results show that chitosan/cellulose porous composites exhibit 3-dimensional interconnected porous structure and chitosan particles facilitate the formation of pores. TGA demonstrates that the addition of chitosan particles improves the thermal stability of cellulose porous materials. XRD presents that the crystalline structure of cellulose is converted from cellulose I to cellulose II in original cellulose during dissolution and regeneration. When the cellulose content is relatively low (≤4wt%), the incorporation of 1wt% chitosan powders increases the porosity of the chitosan/cellulose porous composites. Mechanical properties of chitosan/cellulose porous composites increase with increasing cellulose contents, while water absorption ability decreases. The porosity of the chitosan/cellulose (mass ratio is 1:3) porous composites is 72.7%, the water absorption rate and relative retention rate are 28.0 g/g and 17.6 g/g, the breaking strength and breaking elongation are 0.32 MPa and 25.4%, receptively. This chitosan/cellulose porous composites as excellent absorption material can be used for medical dressing with high performances.