Objective To explore the application and clinical effect of ropivacaine incision infiltration combined with Wiltse approach in the analgesia of lumbar multi-segment decompression and fusion internal fixation. Methods A total of 120 patients with lumbar spinal stenosis and (or) lumbar disc herniation, who received posterior lumbar multisegmental (≥2) transforaminal lumbar interbody fusion (TLIF) in the Second Affiliated Hospital of Nantong University from Jan. 2016 to Jan. 2019, were randomly assigned to four groups: group A (ropivacaine incision infiltration＋Wiltse approach), group B (ropivacaine incision infiltration＋posterior median approach), group C (saline incision infiltration＋Wiltse approach) and group D (saline incision infiltration＋posterior median approach). The operation time, intraoperative blood loss, postoperative drainage volume, postoperative analgesic dosage, the visual analogue scale (VAS) score of low back pain before operation and 6 h, 1 d, 3 d, 7 d, 1 month and 3 months after operation, and the Oswestry disability index (ODI) before operation and 3 d, 7 d, 1 month and 3 months after operation, were compared among the four groups. Results There were no significant differences in gender, age, body weight, operative segments, low back pain VAS score or ODI before operation (all P＞0.05). The intraoperative blood loss, postoperative drainage volume and analgesic dosage were significantly lower in the groups A and C than those in the groups B and D (all P＜0.05). The VAS scores 6 h after operation were significantly lower in the groups A and B than those in the groups C and D, and the VAS scores 3 and 7 d after operation were significantly lower in the groups A and C than the groups B and D (all P＜0.05). The ODI values 3 d and 3 months after operation were significantly lower in the groups A and C than those in the groups B and D (all P＜0.05). Conclusion Preemptive analgesia using ropivacaine incision infiltration combined with Wiltse approach in lumbar multi-segment decompression and fusion internal fixation can effectively relieve postoperative pain, with remarkable analgesic effect and rapid functional recovery, benefiting early recovery of patients after operation.