Coronavirus disease-2019 (COVID-19) has rapidly spread worldwide. High-flow nasal cannula therapy (HFNC) is a major oxygen supporting therapy for severely ill patients, but information regarding the timing of HFNC application is scarce, especially in elderly patients. We retrospectively analyzed the clinical data of 110 elderly patients (≥65 years) who received HFNC from Renmin Hospital of Wuhan University, People's Hospital of Xiantao City and Chinese Medicine Hospital of Shishou City in Hubei Province, China, and from Affiliated Hospital of Guangdong Medical University, People's Hospital of Yangjiang City, People's Hospital of Maoming City in Guangdong Province, China. Of the 110 patients, the median age was 71 years (IQR, 68-78) and 59.1% was male. Thirty-eight patients received HFNC when 200 mmHg < PO2/FiO2 ≤ 300 mmHg (early HFNC group), and 72 patients received HFNC treatment when 100 mmHg < PaO2/FiO2 ≤ 200 mmHg (late HFNC group). Compared with the late HFNC group, patients in the early HFNC group had a lower likelihood of developing severe ARDS, longer time from illness onset to severe ARDS and shorter duration of viral shedding after illness onset, as well as shorter lengths of ICU and hospital stay. Twenty-four patients died during hospitalization, of whom 22 deaths (30.6%) were in the late HFNC group and 2(5.3%) in the early HFNC group. It is concluded that the prognosis was better in severely ill elderly patients with COVID-19 receiving early compared to late HFNC. This suggests HFNC could be considered early in this disease process.