Objective: To compare the effects of two different liquid in negative pressure wound therapy for chronic wounds, provide the reference for clinical application. Methods: The growth of granulation tissue, pain degree, plugging rate, average hospitalization days, bacterial culture and drug sensitivity test results were compared after the two liquid was used. Results: Nitrofural group compared with the saline group can promote the growth of granulation tissue[(9.41±1.12) vs (7.76±0.67)], shorten the average days of hospitalization[(29.44±1.88) vs (32.79±1.74)]; but for the relief of pain degree and the plugging rate, the effects was similar(P＞0.01, the difference was not significant). At the same time, bacterial test showed that there were almost gram-negative bacteria, bacteria detection rate (62.5%) in Nitrofural group was less than that in the saline group (82.5%); Nitrofural group has more nitrofurazone resistant bacteria(68%), and the saline group performs not the same(36.36%). Conclusion: ① Furacilin irrigation could promote the growth of granulation tissue, shorten the average hospitalization days. ②The two methods can effectively prevent the blockage of the drainage tube. ② Furacilin irrigation can reduce the detection rate of bacteria, but cannot prevent the resistance of nitrofurazone.