Objective To investigate the clinical effect of minimally invasive transforaminal lumbar inter⁃ body fusion（TLIF）by multifidus ⁃splitting approach in the treatment of lumbosacral degenerative diseases. Methods A total of 127 patients with lumbosacral single ⁃ level degeneration who met the inclusion criteria from February 2017 to February 2021 were selected as the study subjects. According to different surgical approaches，the patients were divided into treatment group（n = 62）and control group（n = 65）. Patients in the treatment group received TLIF surgery after median incision and splitting of multifidus muscle，while patients in the control group received TLIF surgery after traditional paravertebral muscle dissection. Lumbar Oswestry Disability Index（ODI）and JOA scores，visual analogue scale（VAS）scores，intraoperative blood loss，operation time，postoperative drainage， length of hospital stay，and multifidus fat infiltration grade were compared between the two groups before and after treatment and at 1⁃year follow⁃up. Results The amount of intraoperative blood loss，operation time，postoperative drainage volume and length of hospital stay in the treatment group were lower than those in the control group，with statistical significance（P < 0.05）. There were no statistically significant differences in preoperative ODI and JOA scores between 2 groups（P > 0.05），but ODI score in treatment group was lower than control group and JOA score was higher than control group at 3 days and 1 year follow⁃up after surgery，with statistically significant differences （P < 0.05）. There was no statistically significant difference in preoperative VAS scores between 2 groups（P > 0.05）， and VAS scores of 3 days and 1 year after surgery in the treatment group were lower than those in the control group. The difference was statistically significant（P < 0.05）. One year after surgery，the proportion of higher fat infiltra⁃tion grade of multifidus muscle in the treatment group was significantly lower than that in the control group，and the difference was statistically significant（P < 0.05）. Conclusion Compared with traditional approach，TLIF by splitting the multifidus approach for the treatment of lumbosacral single ⁃segment degenerative disease can signifi⁃ cantly improve the lumbar function of patients，and has the advantages of less bleeding，less postoperative pain， short operation time，and short hospital stay. It can reduce the adipose formation of multifidus muscle ，retain its function，and has the advantages of minimally invasive surgery，and promote the rapid perioperative recovery of patients.