Objective To evaluate whether low-dose ropivacaine in combination with sufentanil could produce effective spinal anaesthesia for severe preeclamptic parturients during cesarean section.Methods 40 severe preeclampsia parturients undergoing elective caesarean delivery under combined spinal-epidural anaesthesia were randomly divided into two groups based on a computer-generated grouping number sheet,each group in 20 cases.Group A received intrathecal ropivacaine 15mg (1.5mL)+10% dextrose 1mL with normal saline 0.5mL.Group B received intrathecal ropivacaine 10mg (1mL) + sufentanil 5μg(1mL) + 10% dextrose 1mL.Blood pressure,heart rate and oxygen saturation were documented at 2 min intervals for 10 min after local anaesthetic was administered.Sensory and motor block were assessed at 2.5 min intervals after spinal injection.The side effects such as hypotension,nausea and vomiting during surgery were recorded.Results The onset of motor block was longer[(4.8±2.1) min vs.(4.2±1.5) min,t=-2.83,P<0.01],and the duration was shorter[(75.9±25.2) min vs.(115.4±29.5)min,t=10.75,P<0.01] in group B than those in group A.The number of patients who had Bromage score 3 in group A was more than that in group B.Compared with group A,the duration of complete analgesia[(180±35) min vs.(120±27) min,t=15.48,P<0.001]and effective analgesia[(245±29)min vs.(184±34)min;t=16.21,P<0.001] increased in group B.More patients were sleepy but easily rousable in group B than in group A (9cases vs.0cases,χ2=8.53,P<0.01).The incidence rate of hypotension was significantly higher(45.0% vs.20.0%,χ2=4.29,P<0.05) in group A than that in group B.Compared with group A,the incidence rate of hypotension(45.0% vs.20.0%,χ2=4.29,P<0.05),vomiting(30.0% vs.5.0%,χ2=4.33,P<0.05) and shivering (50.0% vs.10.0%,χ2=7.62,P<0.01) were lower in group B.The incidence of pruritus was significantly higher in group B (χ2=10.16,P<0.01).Conclusion Hyperbaric ropivacaine 10 mg with sufentanil 5μg could produce effective spinal anaesthesia for severe preeclamptic parturients during cesarean section with less hypotension,vomiting and shivering,and longer lasting analgesia than hyperbaric ropivacaine 15 mg.