Abstract: [Objective] To explore the effect of transforaminal lumbar interbody fusion (TLIF) combined with unilateral pedicle screw fixation in the treatment of degenerative lumbar diseases (LDD) and the degree of cage subsidence. [Methods] 127 patients with LDD who treated by TLIF combined with unilateral pedicle screw fixation were enrolled, of which 55 patients who were underwent unilateral pedicle screw fixation as unilateral group,72 patients who were underwent bilateral pedicle screw fixation as bilateral group. The pain Visual Analog Scale (VAS) score, Oswestry Dysfunction Index (ODI) were evaluated, the intervertebral height of fusion segment was measured by CT and cage subsidence was calculated. [Results] The incision length, intraoperative blood loss, operation time, postoperative hospital stay, incidence of paravertebral fibrosis and adjacent segment degeneration (ASD) in the unilateral group were lower than those in the bilateral group (P<0.05),the rates of recent complications and bone graft fusion were not significantly different between the two groups (P>0.05).There was no significant difference in age subsidence rate, VAS score, and ODI score between the two groups(P>0.05), and there was no statistically significant difference between 1-level and 2-level fusion (P>0.05). [Conclusion] TLIF combined with unilateral pedicle screw fixation for the treatment of LDD can achieve long-term effects similar to bilateral internal fixation, and has no significant effect on the settlement of the cage.