Objective To study the diagnostic value of serum N-terminal probrain natriutetic peptide (NT-proBNP) level and its influencing factors in very old male heart failure (HF) patients with preserved ejection fraction.Methods Two hundred and thirty-six very old male HF patients with preserved ejection fraction admitted to our hospital from February 2008 to July 2016 were divided into HF group (n=92) and HF-free grup (n=144).Their biochemical parameters were tested and analyzed by correlation analysis.Results The serum NT-proBNP level and logNT-proBNP were significantly higher in HF group than in HF-free group (2205.4±2128.4 ng/L vs 457.3± 312.2 ng/L,P=0.000;3.3±0.3 vs 2.5±0.3,P=0.004).Univariate correlation analysis showed that serum NT-proBNP level was positively related with AF,diuretics,LVEF,left atrium diameter,eGFR,creatinine and logcTnI (P＜0.05,P＜0.01).Multivariate linear regression analysis revealed that AF,LVEF,left atrium diameter,eGFR,and logcTnI were the independent risk factors for NT-proBNP and that NT-proBNP was negatively related with LVEF and eGFR.Conclusion The serum NT-proBNP level in very old male HF patients with preserved ejection fraction can be influenced by a variety of factors.Increasing LVEF and eGFR can reduce their serum NT-proBNP level and improve their outcome.