Abstract: Objective To observe the effectiveness of different concentrations of oxygen on the resuscitation of preterm infants.Methods Prospective single-blind randomized controlled method was used in this study.468 premature infants who gestational age ≥32 weeks and after the first 30 s preliminary recovery still had positive pressure ventilation indications were selected as the study objects,and they were divided into two groups randomly,A group (n=175 patients) were adopted 21% oxygen concentration to recover,B group (n=293 patients) were adopted 40% oxygen concentration to recover.In the process of recovery,systematically adjusting oxygen concentration was used to keep oxygen saturation in the target range.The recovery effect between the two groups was compared.Results The effective rate in 1 minute was 89.2% in group A and 95.2% in group B,and the difference was statistically significant (χ²=6.177,P<0.05).The effective rate in 2 minutes was 97.7% in group A and 77.3% in group B,and the difference was statistically significant (Fisher chi-square test,P<0.001).The effective rate in 3 minutes was 98.6% in group A and 95.8% in group B,and the difference was not statistically significant (Fisher chi-square test,P>0.05).The effective rate in 5 minutes was 99.8% group A and 90% in group B,the differences was statistically significant (Fisher chi-square test,P<0.05).Conclusion(1) The recovery effective of 40% oxygen concentration in preterm infants recovery was better than that of 21% oxygen concentration.Once pulmonary ventilation established after birth,21% oxygen concentration can be maintained up to standard.(2) The majority of preterm infants recovered with 21% oxygen were effective and feasible,especially on the nearly full-term infants.