The purpose of this study is to evaluate the effect of Xinyue Capsule in the improvement cardiac function and reduction the level of heart failure biomarker NT-proBNP in patients suffering from HF with an ejection fraction greater than or equal to 50%. Researchers will also collect information on how much the heart disease has impact on patient's lives, and how well Xinyue Capsule treatment is tolerated. The study plans to enroll 246 male and female patients of the age of 18 years and above suffering from heart failure with ejection fraction greater than or equal to 50%. Participants will take the study product as oral tablet with a dose 0.6 g Tid daily. Study duration will be up to 12 weeks.