Abstract: The effect of LiCl on the viscosity of polyurethaneurea(PUU) solution,and structures and properties of PUU films was studied by using FT-IR and DSC.The results show that the viscosity of PUU solution decrease first by adding LiCl,but then increase.Because of the coordination of LiCl with ether and carbonyl groups existed in the PUU films,the value of T_g and the degree of ordered hydrogen bonding of urethane groups in the PUU films increased by adding LiCl into PUU films,but the degree of ordered hydrogen bonding of urea groups in the PUU films decreased.The tensile modulus,hardness and tear strength of the PUU films can be enhanced appreciably by adding LiCl into the PUU films.However,the water absorption of the PUU films containing LiCl was higher than that of the PUU film without LiCl.