Abstract: OBJECTIVE To observe the preventive effect of Demolin spray on incisional infection in patients with fracture treated with external fixator. METHODS A total of 116 patients treated with external fixator from Jan. 2015 to Jan. 2016 were selected as research objects, and were randomly divided into two groups, with 58 cases in each group. Patients in control group received conventional treatment, and patients in experimental group received Demolin spray. The healing rate, the dressing frequency and the pathogen infection of the two groups were compared. RESULTS The number of daily dressings in experimental group was significantly lower than that in control group (P<0.05). The incidence of sured and swollen and exudation of experimental group were 13.79% and 12.07%,which were 32.76%and 34.48% of control group,and the differences were statistically significant (P<0.05). 7 days and 14 days after operation, the pinhole infection rates of experimental group was 3.79% and 9.20%,the pinhole infection rates of control group were 17.49% and 28.71%,and the difference was statistically significant (P<0.05).On the 14th day, two groups of infected patients were subjected to bacterial culture, there were 7 cases of infection in experimental group, and 16 cases of infection in control group, with the infection rates of 12.07% and 27.59%. The infection rates in the two groups was statistically different (χ²=4.3927, P<0.05). Eight strains of pathogenic bacteria were isolated from experimental group and 19 strains were isolated from control group. Staphylococcus aureus had the highest proportion in the isolated bacteria of the two groups, accounting for 50.00% and 42.11%. CONCLUSION Dermolin spray can effectively prevent postoperative external fixation stent in patients with pinhole infection, and S. aureus is the main cause of infection of pathogens.