The H2FPEF score, a convenient tool developed for diagnosing heart failure with preserved ejection fraction (HFpEF), exhibited useful prognostic utility in HFpEF. However, the applicability and the prognostic value of the H2FPEF score in Chinese HFpEF patients have yet to be fully confirmed. The study aimed to evaluate the effect of modified H2FPEF score on the prognosis of Chinese HFpEF patients. In this retrospective study, we calculated the H2FPEF scores by body mass index (BMI) ≥ 25 kg/m2 and 30 kg/m2 respectively, for 497 consecutive HFpEF patients in China. Subjects were divided into low- (0 - 3 points), intermediate- (4 - 6 points), and high-score (7 - 9 points) groups. The primary and secondary endpoints were heart failure (HF)-related events and acute coronary syndrome (ACS), respectively. Cox proportional hazard models were applied to calculate hazard ratios (HRs). Receiver operating characteristic (ROC) curves and areas under the curve (AUC) were used to evaluate the prediction of the H2FPEF score for adverse outcomes. Over a mean follow-up of 40.46 ± 6.52 months, the primary and secondary endpoints occurred in 168 patients (33.8%) and 97 patients (19.5%), respectively. By the definition of obesity as BMI ≥ 25 kg/m2, a higher incidence of HF-related events and ACS was observed among those with a higher modified H2FPEF score. The modified H2FPEF significantly predicted HF-related events (AUC: 0.723; 95% confidence interval (CI): 0.676 - 0.770; P < 0.001) and ACS (AUC: 0.670; 95% CI: 0.608 - 0.731; P < 0.014) with higher power than the H2FPEF score calculated by BMI ≥ 30 kg/m2. The cutoff of the modified H2FPEF score was 6.5 for detecting HF-related events and ACS. The modified H2FPEF score, using BMI ≥ 25 kg/m2 to define obesity, could more effectively predict the occurrence of subsequent cardiovascular events in Chinese HFpEF patients. The modified H2FPEF score above 6.5 is a risk factor for adverse cardiovascular events in HFpEF patients.