Objective:To reevaluate the systematic reviews on application effect of high-flow nasal cannula oxygen therapy in preterm infants.Methods:Systematic reviews or Meta-analysis on the use of high-flow nasal cannula oxygen therapy in preterm infants were searched by computer from Cochrane Library, PubMed, Embase, CNKI and Wanfang databases. The retrieval period was from establishment of databases to December 6, 2022. Literature screening and data extraction were conducted independently by two researchers. A Measure Tool to Assess Systematic ReviewsⅡ and The Grading of Recommendations Assessment, Development and Evaluation system were used to evaluate the methodological quality and evidence quality grading of the included literature, respectively.Results:A total of 13 systematic reviews were included, and the results showed that the methodological quality of 4 literatures was low, and that of 9 literatures was very low. The hierarchy of evidence of 112 outcome indicators was evaluated. The results showed that the evidence quality of 7 outcome indicators was extremely low, evidence quality of 78 was low, evidence quality of 26 was intermediate and 1 was high.Conclusions:High-flow nasal cannula oxygen therapy is not sufficient to replace the role of non-invasive positive pressure ventilation in respiratory support for premature infants, but it can reduce the incidence of nasal injury and the incidence of air leakage or pneumothorax in respiratory support after extubation. The methodological quality of systematic evaluation included in the study is low, and the credibility of evidence is insufficient. Clinical application needs to carefully adopt relevant evidence and further carry out more standardized and rigorous research.