Objective To explore the effects of different starting doses of Dopamine for hypotension and the influences of brain in the prematurity. Methods Fifty-six preterm infants with hypotension were enrolled in the study after one dose of isotonic solution, and they were divided into 2 groups as group A and group B. The patients in the 2 groups both received Dobutamine at 2.5 μg/(kg·min). Group A also received Dopamine of starting dose at 2.5 μg/(kg·min), group B received Dopamine of starting dose at 5.0 μg/(kg·min), and the dose increased by 2.5 μg/(kg·min) in a stepwise fashion every 20 minutes until the mean blood pressure(MBP)≥115% of the weeks of the gestational age or a maximal dose of 15 μg/(kg·min). The MBP, heart rate, peripheral blood glucose, urine output, fluid intake, carbohydrate debit and the need for insulin therapy during the 96 h of the treatment were monitored.Before medicine administration, a complete cerebral ultrasound scan was made, and repeated every 1-2 weeks, the initial and final cerebral ultrasound diagnosis were analyzed.Duration of respiratory support, incidence of bronchopulmonary dysplasia(BPD), patent ductus arteriosus(PDA), the time of full enteral nutrition were recorded, niecrotizing enterocolitis(NEC) and bowel perforation. Results Compared with group A, the mean drug dose and maximum infusion required to normalize blood pressure were significantly higher in group B[(10.42±3.27) mg/kg vs(8.24±3.99) mg/kg, P 0.05). The blood pressure 6 hours after the Dopamine can maintain at stable level, and the difference was not statistically significant(P>0.05). Conclusions The larger starting dose of Dopamine can raise the blood pressure effectively, but it has potential intestinal and brain hypoxia injury.More trials are needed with larger sample size for further study. Key words: Dopamine; Hypotension; Infant, preterm