Objective To Observe the clinical efficacy of modified Sijunzi decoction in the treatment of heart failure with reduced ejection fraction of Qi deficiency and blood stasis syndrome. Methods A total of 106 patients with heart failure with reduced ejection fraction of Qi deficiency and blood stasis syndrome were selected from September 2021 to September 2022 and divided into an observation group and a control group according to the random number table method，with 53 patients in each group. The control group was continuously treated with conventional Western medicine，while the observation group was treated with modified Sijunzi decoction on the basis of the control group for 10 days. NT-proBNP，left ventricular ejection fraction （LVEF）， the traditional Chinese medicine pattern score，6-minute walk test （6MWT），Minnesota Heart Failure Quality of Life Questionnaire （MLHFQ），Lee's heart failure score，the clinical efficacy and safety were evaluated between the two groups. Results After treatment， there was no significant change in LVEF in both groups compared to the baseline， but NTpro-BNP was markedly declined in both groups （P < 0.05）， but there was no significant difference between the two groups （P > 0.05）. Lee's score， MLHFQ score and the traditional Chinese medicine pattern score in both groups were significantly reduced， and the difference was statistically significant （P < 0.05），those scores were lower in the observation group than in the control group （P < 0.05）. 6MWT in both groups was higher than before （P < 0.05），and 6MWT in the observation group was higher than that in the control group （P<0.05）. The therapeutic effect and safety were higher in the observation group than in the control group. Conclusions Modified Sijunzi decoction combined with conventional Western medicine therapy for the patients with heart failure with  reduced ejection fraction of Qi deficiency and blood stasis syndrome can effectively improve the clinical symptoms and quality of life， and the efficacy is safe.