The characteristics and properties of bacterial cellulose and dialdehyde celluloses from bacterial cellulose were studied by XRD, TG-IR and adsorption capacity testing. The crystal cell parameters of BC were calculated and approximated to that of monocline crystal cell model. The XRD profiles showed that the crystallinity degree of BC was 66%, and that of the DACs (12% aldehyde) was 56%. The optimal adsorption capacities of pure water on dried BC and DAC were 12 g/g and 3.1 g/g respectively, and that of iron ion on dried BC and DAC were 11 mg/g and 6.9 mg/g respectively. And the optimal adsorption capacity of hexanediamine on DAC was 700 mg/g, and that of n-phenylene diamine on DAC was 490 mg/g. The IR result showed that the adsorption of hexanediamine on DAC was physical adsorption, not chemical reaction under the experimental conditions.