Abstract: In this paper, the new chitosan derivatives, i.e., dehydroabietylamine-chitosan cationic surfactants(a, b and c), were synthesized with chitosan (1 000, 1 500, 3 000) and dehydroabietylamine as starting material. The cationic surfactants were characterized by FT-IR and 1H NMR , respectively. The surface activities, emulsifying properties and antibacterial properties of the products were also investigated. The results showed that the critical micelle concentrations (CMC) of a, b and c are 3.98×10-4, 2.51×10-3 and 5.01×10-3 mol/L at 25 ℃, respectively. The γcmc of a, b and c are 38.6, 36.8 and 36.6 mN/m, respectively. The emulsifying time of these three surfactants are 44, 71 and 148s, respectively. The antibacterial properties of the target products were tested with the minimum inhibitory concentration method. The preliminary result indicated that those compounds have some antibacterial activity. In particular, the antibacterial activities of the compounds a, b and c against Escherichia aerogenesare are superior to the commercially available fungicides bromogeramine and ampicillin sodium and their minimum inhibitory concentration are 2, 2 and 4 mg/L, respectively. The antibacterial activities of products would be enhanced with the increase of the DS and would be decreased with the increase of the chitosan molecular weight.