Objective:To explore the feasibility of high-flow nasal cannula(HFNC)therapy for respiratory failure in elderly patients.Methods:A total of 300 patients with respiratory failure admitted to Peking University Shougang Hospital from December 2016 to March 2019 were enrolled in this prospective study.Patients were divided into three groups: the HFNC group, the conventional oxygen therapy(COT)group and the non-invasive positive pressure ventilation(NPPV)group(n=100 in each group). Arterial oxygen saturation(SPO 2), oxygen index(OI), heart rate(HR), respiratory rate(RR), mean arterial pressure(MAP), comfort level, discharge rate, tracheal intubation rate, rate of referral to ICU, mortality and rate of referral to another group after therapy were compared between the HFNC and COT groups and between the HFNC and NPPV groups. Results:SPO 2 after oxygen therapy for 30 minutes( t=-2.992, P=0.003), 1 hour( t=-2.884, P=0.005)and 6 hours( t=-3.196, P=0.002)and OI before discharge( t=-2.060, P=0.048)were higher in the HFNC group than in the COT group.The HR in the above two groups was lower before discharge than before therapy, and the HR in the COT group was even lower(73.1±25.1 beat per minute vs.75.1±25.9 beat per minute), but both were within the normal range.The discharge rate was higher( χ2=-1.969, P=0.049), while the rate of referral to another group was lower in the HFNC group than in the COT group( χ2=-3.115, P=0.002). There was no significant difference in the tracheal intubation rate, ICU transfer rate and mortality between the HFNC and COT groups.SPO 2 after oxygen therapy for 30 minutes( t=-2.026, P=0.046)and 6 hours( t=-2.101, P=0.040)were higher in the HFNC group than in the NPPV group, but there was no significant difference in OI and SPO 2 between the two groups before discharge.The HR in both HFNC and NPPV groups was lower before discharge than before therapy, and there was no statistical difference between the two groups.The mortality, discharge rate, tracheal intubation rate, ICU transfer rate and rate of referral to another group had no significant difference between the HFNC and NPPV groups.The comfort level was higher in the HFNC group than in the COT and NPPV groups( t=-3.758 and -19.180, both P=0.000). Conclusions:HFNC is a new type of oxygen therapy equipment introduced after COT and NPPV, and possesses more advantages for elderly patients with respiratory failure.