ObjectiveTo evaluate the effects and safety of the optimized new Shengmai Powder （优化新生脉散方） on exercise tolerance in patients with chronic heart failure （CHF） of qi deficiency， blood stasis， and fluid retention syndrome. MethodsA randomized， double-blind， placebo-controlled trial was conducted. A total of 78 CHF patients with qi deficiency， blood stasis， and fluid retention syndrome were recruited and randomly assigned to a treatment group （39 cases） and a control group （39 cases）. On the basis of conventional western medical therapy， patients in the treatment group additionally received the optimized new Shengmai Powder granules， while the control group was given an oral placebo of optimized new Shengmai Powder granules. Patients in both groups took 30.6 g each time， twice a day， mixed with water for administration， with a total treatment course of 4 weeks. The primary outcomes were 6-minute walk distance （6MWD） and peak oxygen uptake （Peak VO₂） measured by cardiopulmonary exercise testing. Secondary outcomes included New York Heart Association （NYHA） functional classification， B-type natriuretic peptide （BNP） levels， cardiac function indexes including left ventricular ejection fraction （LVEF）， left ventri-cular end-systolic diameter （LVESD） and left ventricular end-diastolic diameter （LVEDD）， Minnesota Living with Heart Failure Questionnaire （MLHFQ） scores， and scores of four diagnostic information of traditional Chinese medicine （TCM）. All indicators were assessed once before and after treatment respectively. Safety indicators were evaluated， and adverse events during the trial were recorded. ResultsAll patients in both groups were included in the full ana-lysis set （FAS） and safety set （SS）. Compared with baseline， the 6MWD and Peak VO₂ of cardiopulmonary exercise test in the treatment group significantly increased after treatment， while the MLHFQ scores， serum BNP levels and scores of TCM four diagnostic information significantly decreased， and the NYHA cardiac function grade significantly improved （P＜0.01）. After treatment， the 6MWD and Peak VO₂ of cardiopulmonary exercise test， as well as their changes from baseline in the treatment group were higher than those in the control group； the MLHFQ scores， serum BNP levels and scores of TCM four diagnostic information in the treatment group were lower than those in the control group； and the improvement of NYHA cardiac function grade in the treatment group was superior to that in the control group （P＜0.01）. There was no statistically significant differences in all indicators after treatment in the control group （P＞0.05）. The incidence of adverse events was 5.1% （2/39） in the treatment group and 2.6% （1/39） in the control group， with no statistically significant difference between groups （P＞0.05）. ConclusionOn the basis of conventional western medicine treatment， the addition of the optimized new Shengmai Powder can further improve exercise tolerance， cardiac function and quality of life in patients with CHF of qi deficiency， blood stasis and fluid retention syndrome， and show good safety.