Abstract: Objective:To compare the effects of postoperative analgesia between continuous lumbar plexus block and femoral nerve block in total knee replacement.Methods:Seventy-four patients treated with total knee replacement surgery from December 2014 to September were randomly divided into the continuous femoral nerve block group and continuous lumbar plexus block group(37 cases each group).The scores of VAS of resting after 4 h,8 h,16 h and 32 h of operation,and acting after 16 h and 32h of operation in two groups were recorded.The scores of knee joint function in two groups before operation and after 2 weeks and 10 weeks of operation were evaluated.The incidence rates of adverse reaction in two groups were recorded.Results:The scores of VAS of resting after 4 h,8 h,16 h and 32 h of operation,and acting after 16 h and 32 h of operation in continuous lumbar plexus block group were significantly lower than those in continuous femoral nerve block group(P<0.05 to P<0.01).Compared before operation,the HSS scores of preoperative 2 weeks and 12 weeks in two groups significantly increased(P<0.01).The incidence rate of adverse reaction in continuous femoral nerve block group(37.84%) was significantly higher than that in continuous lumbar plexus block group(16.22%)(P<0.05).Conclusions:The effect of continuous lumbar plexus block group on postoperative analgesia in knee replacement is better than that of the continuous femoral nerve block,the adverse reaction of which is light,which has important clinical significance.