[Objective] To investigate the feasibility of PEEK rod pedicle screw system non-fusion fixation combined with spinal canal decompression in the treatment of three-level lumbar degenerative diseases. [Methods] From January 2018 to December 2019, 62 patients with three-levels lumbar degenerative diseases who met the inclusion and exclusion criteria were prospectively collected. According to preoperative informed communication, they were divided into non-fusion group (n=30) and fusion group (n=32). The perioperative, follow-up and imaging results were compared between the two groups. [Results] There were no significant differences in postoperative drainage volume, incision length, incision healing grades, postoperative walking time and hospital stay between the two groups(p>0.05). The operation time and intraoperative blood loss of non-fusion group were lower than those of fusion group(p<0.05), and there was no significant difference in postoperative drainage volume between the two groups(p>0.05). VAS score, ODI index and LSDI score of the two groups were improved compared with those before operation(p<0.05). There was no significant difference between the two groups at each follow-up time point after operation(p>0.05); There was no significant difference in LSDI scores between the two groups at 3 months after operation(p>0.05), the non-fusion group was better than the fusion group at 12 months and last follow-up(p<0.05). The fixed segment ROM of the non-fusion group was greater than that of the fusion group at 12 months and last follow-up(p<0.05). At last follow-up, the upper adjacent segment ROM of the non-fusion group was smaller than that of the fusion group(p<0.05), and the Pfirrmann grade of the adjacent intervertebral disc in the non-fusion group was better than that in the fusion group(p<0.05). [Conclusion] PEEK rod non-fusion fixation and titanium rod fusion fixation combined with spinal canal decompression in the treatment of three-levels of lumbar degenerative diseases achieved good clinical efficacy. Non-fusion can retain partial fixed segment range of motion, reduce the stiffness of the patient's back, and have relatively little effect on the degeneration of adjacent segment intervertebral disc.