【Abstract】 Objective To explore the effects of different doses of caffeine citrate on respiratory mechanics before extubation in preterm infants and to guide extubation. Methods 90 preterm infants with mechanical ventilation more than 48 hours and gestational age less than 37 weeks admitted to our hospital from July 2015 to July 2017 were randomized into caffeine highdose caffeine group, lowdose group and the control group. Under the treatment of the active antiinfective, stable internal environment, intravenous nutrition support and mechanical ventilation, pulmonary surfactant (pulmonary surfactant, PS) replacement therapy (reactive dose 200 mg/kg) with symptoms and signs of respiratory distress intratracheal administration, the highdose group was treated with caffeine 20 mg/kg.d (10 min), until successfully extracted 24 hours before extubation or within 6 hours of unplanned extubation. Tubes, small holding dose groups were treated with caffeine citrate at 5 mg/kg.d (10 min) until extubation within 24 hours before preparation for extubation or within 6 hours of unplanned extubation. The control group received only routine treatment instead of routine treatment. The clinical data were used to record the ventilator parameters before and after extubation and the blood gas analysis indicators of the groups within 2 hours before and after 2 hours of extubation with citrate caffeine, and before, before and after extubation. The patient's respiratory mechanics changes were recorded 2 hours after the procedure and the ventilatory pattern after extubation was recorded. The successful extubation rate and adverse reactions were recorded. Results After different doses of caffeine citrate were used, the respiratory mechanics of the highdose, lowdose and control groups changed to WOB before extubation (801±876) VS (902±903). VS (1217±995) g·cm/(min·Kg), airway resistance (Raw) (6238±1727)VS (6873±1446) VS (7249±1384) cmH2O/(L·s) Compliance (Cdyn) (20±039) vs (158±030) VS (143±037) mL/cmH2O, P＜005. The blood gas analysis of each group during the first 2 hours of acid caffeine and 2 hours after extubation was compared. The results showed that the blood gas analysis parameters PaCO2 and PaO2 were high in the highdose group and the lowdose group and the control group (P＜005. The overall effective rate of successful extubation of he highdose group, the lowdose group and the control group were 867% , 733% and 567% (P＜005). Among the adverse reactions, there was no significant difference between the highdose caffeine caffeine group and the lowdose group and the control group. Conclusion The highdose group (20mg/kg.d) of caffeine citrate had a positive effect on the preextubation respiratory mechanics. It was helpful for extubation and the success rate was significantly higher than that of the lowdose group and the control group. There was no statistically significant difference between the two groups in adverse reactions, so it is worthy of promotion and application in clinical practice.