Abstract: Objective To explore the protective effect of Dongsheng Fusang decoction on endothelial function in phlegm-dampness type erectile dysfunction patients. Methods A total of 60 patients with phlegm-dampness type erectile dysfunction in our hospital were selected from March 2018 to July 2018,and they were randomly divided into control group (n=30) and observation group (n=30) according to the random number table method. The control group was treated with Tadalafil, and the observation group was took the Dongsheng Fusang decoction on the control group. The clinical efficacy, endothelial function related indexes and incidence of adverse reactions were compared between the two groups before and after treatment. Results Before treatment, there was no statistically significant difference in international erectile function scale (IIEF-5) score, TCM symptom score and maximum erectile hardness between the two groups (P>0.05), after treatment,the IIEF-5score, TCM symptom score and maximum erectile hardness of the two groups were significantly better than those before treatment(P<0.05), and the above indexes in the observation group were obviously better than those in the control group (P<0.05). Before treatment, there was no statistically significant difference in the levels of vasodilatory function (FMD), nitric oxide (NO) and endothelin-1 (ET-1) between the two groups (P>0.05), after treatment, the levels of FMD and NO in the two groups were significantly higher than those before treatment (P<0.05), and the levels of these two indexes in the observation group were significantly higher than those in the control group (P<0.05), the level of ET-1 in the two groups was significantly lower than that before treatment (P<0.05), and the level of ET-1 in the observation group was significantly lower than that in the control group (P<0.05). No obvious adverse reactions such as headache, blurred vision and drug allergy were observed in either group during the treatment. Only one patient in the observation group presented mild gastrointestinal discomfort symptoms, adverse reactions in the two groups were not statistically significant (P>0.05). Conclusion Dongsheng Fu sang Yin can significantly improve the clinical efficacy of phlegm-dampness type erectile dysfunction patients and it has certain protective effect on endothelial function of patients, which is worth popularizing in clinical treatment, and has a high safety.