To investigate the causes and treatment of contralateral lower limb pain in the early postoperative period after internal fixation with intervertebral fusion for lumbar disc herniation. Methods: A retrospective study was conducted on patients who underwent lumbar disc removal and fusion internal fixation from October 2007 to February 2013. 15 cases of contralateral lower extremity pain occurred in the early postoperative period, including 1 case of intraoperative nail placement with bursting of the pedicle, 3 cases of overpropulsion, 1 case of unpropulsion, 2 cases of disc prolapse from the contralateral side, and 1 case of unknown cause. As a result, four of these cases were reoperatively explored, and the rest were relieved by conservative treatment. Conclusion: Intraoperative nerve root overstretching and stimulation is the main cause of postoperative contralateral lower limb pain, while residual disc prolapse from the contralateral side, poor intraoperative intervertebral space repositioning, nerve root extrusion due to arch root burst and inflammatory factor stimulation are also factors that should not be ignored.