Abstract: 110 cases of full-term pregnancy parturients with ASA grade Ⅰ to Ⅱ were chosen as the objects to be performed cesarean section. They were randomly divided into 5 groups (each included 22 cases) for lumbar anesthesia. The experiment was adopted two arrangements:control group R (to which 2 mL Ropivacaine of w=0.68% (W/W) was used); morphine group RM1-RM4 (to which the morphine of 0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg were respectively used on the base of group R). After that, the condition of newborn was evaluated, and the analgesia after operation was given a mark according to VAS and PHS, besides, the sedative degree of Ramasy and the harmfull reaction during cesarean section period were also investigation. The results showed that both the Apgar score and the value of umbilical artery's qi and blood at 1 or 5 min among each group of newborns are of normal (P>0.05); and for the time of effective analgesia after operation, there was not obvious in group R (3.6 h±2.7 h), but in group RM1 to RM4, painless time of each group was ≥ 12 h, and in group RM2, RM3, RM4, the number of illness cases that painless time was more than 36 h was over 60 percent. Whereas in each morphine group after operation, there was a correlation between cutaneous pruritus and dosage, but was not obvious aggravation in nausea and vomitus (P>0.05) and inhibition to respiration. Thus it was thought that both morphine and Ropivacaine could be safely used in cesarean section and had no effects on the newborn; meantime, the intrathecal injection used the morphine of 0.2 mg to 0.4 mg had a good effect on the postoperative analgesia.