Purpose: To investigate the efficacy of Wallis interspinous dynamic stability implant after lumbar discectomy compared with lumbar discectomy alone for patients with primary lumbar disc herniation. Methods: A total of 77 patients with primary lumbar disc herniation were randomly assigned to receive posterior lumbar discectomy combined with (n =40, Wallis group) or without (n =37, control group) Wallis interspinous dynamic stabilization implantation. The primary outcomes were Visual Analogue Scale (VAS), Japanese Orthopedics Association (JOA) score and Oswestry Disability Index (ODI). The secondary outcomes were intervertebral disc height (DH), range of motion (ROM) of operated segments, complications and the time of surgery. Results: No significant difference was found between the two groups for the VAS, JOA and ODI scores at 1 week after treatment (P=0.572, P=0.763, P=0.243, respectively). Wallis group had better VAS, JOA and ODI scores than that for control group at 12 months (P=0.001, P=0.018, P=0.011, respectively) and last follow-up time (P=0.020, P=0.008, P=0.012, respectively). Wallis group had higher DH than that for the control group at each follow-up moment (P<0.001, P<0.001, P<0.001, respectively). No significant difference was found in ROM between the two groups at 12 months and last follow-up (P=0.203, P=0.180, respectively). The time of surgery was significantly longer in Wallis group than in control group (P=0.006). Two patients of Wallis group and one patient of control group developed intraoperative dural violation. One patients of control group developed recurrent herniated intervertebral disc. Conclusion: Combination treatment may provide benefits comparable to lumbar discectomy alone for patients with lumbar disc herniation. The dynamic stabilization system may diminish complications by restoring the intervertebral disc height and preserving limited motion of the spine.