Objective: To compare the clinical, radiological outcomes and complication of unilateral pedicle screw (UPS) versus bilateral pedicle screw (BPS) in degenerative lumbar diseases after MIS-TLIF. Methods: In this study, we retrospectively analyzed 96 consecutive patients who had two-level MIS-TLIF at IA/L5 and L5/S1 from January 2012 to January 2016 and the clinical and radiological outcome and the complication were compared. Of the 96 patients for analysis, 44 patients underwent unilateral fixation, and 52 patients underwent bilateral fixation. All patients received at least 12 months fellow up. Clinical outcomes were evaluated by VAS, ODI, fusion rate, operation idex and complication. Results: There was no statistically significant difference in baseline demographic characteristics between the two groups (P>0.05). There was a significantly longer operating time, more blood loss and X-ray exposure times in BPS comparing with UPS (P<0.05). Clinical outcomes in two groups such as the pain (VAS) and Oswestry Disability Index (ODI) improved significantly after surgery (P<0.05) and no difference was found between them (P>0.05). No significant difference was found in fusion rate and total complication rate between the two groups (P>0.05). Conclusions: There was no significant difference between the two fixation methods of MIS-TLIF in clinical outcomes and complications. However, unilateral pedicle screw has some superiorities such as shorter operating time, lower cost, less blood loss and X-ray exposure. Unilateral pedicle screw might be more suitable in performing two-level pedicle screw fixation after MIS-TLIF. [ABSTRACT FROM AUTHOR]