Objective To explore the effects of modified long-term low concentration caudal blocking in medium-term drug induced odinopoeia.Methods According to the digital table,63 patients received drug induced odinopoeia were divided randomly into the control group(without analgesis)and treatment group(analgesis).The control group were treated with caudal blocking with mifepristone,premelle and ethacridine lactate.The treatment group received additional treatments of 0.75％ bupivacaine hydrochloride + 2％ lidocaine hydrochloride + morphine sulfate injection based on treatment of the control group.The duration of labor,bleeding volume and severity of pain were recorded and compared between the two groups.Results The duration of labor of the treatment group was (5.33 ±3.77) h,which was significantly shorter than that of the control group [(7.88 ± 2.62) h] (t =8.01,P ＜ 0.05).The severity of pain of the treatment group were all better than those of the control group(all P ＜0.05).There was no significantly statistificant difference in bleeding volume between the two groups (t =4.63,P ＞ 0.05).Conclusion Application of modified long-term low concentration caudal blocking in medium-term drug induced odinopoeia has confirmed analgesis effects,and can shorten duration of labor without increasing bleeding volume.