Objective To compare the clinical efficacy and adverse effects of caffeine citrate in apnea prevention and treatment of very low birth weight (VLBW) infants at different starting time. Methods Totally 126 VLBW infants born at Huzhou Maternity and Child Health Care hospital from May,2014 to February,2017 were analyzed.65 VLBW infants first given caffeine citrate within two hours after the birth were early treatment group[The first dose were given at (1.2±0.4) hours after the birth] and 61 VLBW infants who were given caffeine citrate after appearing apnea were conventional treatment group[The first dose were given at (30.8±20.5) hours after the birth].The first dose of 20 mg/kg was given by intravenous infusion,a dose of 5 mg/kg after 24 hours,and once every 24 hours.The clinical efficacy and adverse effects of two groups were compared. Results 1)The incidence of AOP after 24 hours treatment,intervention duration of caffeine citrate,duration of oxygen therapy,duration of noninvasive ventilation,duration of tracheal intubation mechanical ventilation and time to reaching full milk feeding in early treatment group were better than those in conventional treatment group,and the differences were statistically significant (P<0.05).The differences of noninvasive ventilation rate and tracheal intubation mechanical ventilation rate in two groups were not statistically significant (P>0.05).2)The incidence rates of ventricular hemorrhage,retinopathy of prematurity,bronchial and pulmonary dysplasia in early treatment group were lower than those in the conventional treatment group,and the differences were statistically significant (P<0.05);The incidence of necrotizing enterocolitis and mortality were not significantly different in two groups (P>0.05).3)The incidence of electrolyte disorder in early treatment group was higher than conventional treatment group,the difference was statistically significant (P<0.05).There was no significant difference on the incidence of other adverse reactions in two groups (P>0.05). Conclusion The efficacy and prognosis of early use of caffeine citrate maybe better than that regular given after apnea for apnea prevention and treatment in VLBW infants,and the adverse effects do not increase obviously.