<正>Objective:To test the characteristics of hyaluronic acid（HA）derivative cross-linked by polyethylene glycol films of low water content.Methods:The cross-linked HA film with 200μm thickness was got at atmospheric pressure at 25℃for 5 d.After dried

cross-linked films of 10 mm×10 mm were weighed and immersed in phosphate buffered saline （PBS pH 7.45）at 37℃for 24 h.Then the solution fraction and water content were estimated.Meanwhile

cross-linked HA derivative films were immersed in phosphate buffered saline（PBS:pH 7.45）at 37℃for determined time and then implanted subcutaneously in the back of white rats to test in vitro or in vivo degradation characteristic.Results and Conclusion:HA hydrogel cross-linked by polyethylene glycol with water content is as low as 60% and this kind of HA derivative has a slow degradation rate.