Abstract: Objective: To examine the efficacy of continuing low-flow non-humidified nasal cannula oxygen therapy.Methods: We searched the databases such as CBMdisc, CNKI, VIP, PubMed, EMbase, Web of Science and Cochrane library to gather the studies on low-flow non-humidified nasal cannula oxygen therapy of which those were under the randomized controlled trials (RCTs) and quasi- randomized controlled trials. The quality of studies was evaluated and the data were selected by two independent reviewers. Results: Twelve RCTs were finally included and they were at medium level in quality. The meta-analysis showed little significant difference in respiratory symptoms between the two groups(P>0.05), but there was statistically difference in the incidence of humidifier pollution and respiratory tract infection,operating time of oxygen therapy and patients' satisfaction (P<0.05). Conclusion: The continuing low-flow non-humidified nasal cannula oxygen therapy could reduce the incidence of humidifier pollution and respiratory tract infection. The technique also could shorten operating time of oxygen therapy and improve patients' satisfaction with little respiratory symptoms. Research from multicenter RCTs should be beneficial to further confirm the result.