Abstract:[Objective] To investigate the factors related to early surgical site infection (SSI) after posterior lumbar interbody fusion (PLIF). [Methods] A total of 468 patients who underwent PLIF surgery in our hospital from January 2019 to January 2022 were included in this study. The occurrence of postoperative SSI was observed, and the related factors of SSI were explored by univariate comparison and multiple logistic regression analysis. [Results] The SSI occurred in 18 of 468 patients, accounted for 3.9%. The infection group proved significantly greater than the non-infection group in terms of women proportion [male/female, (5/13) vs (232/218), P=0.048], age [(59.7±7.2) years vs (56.3±8.5) years, P=0.012], preoperative diabetes mellitus [no/mild/medium/severe, (13/2/2/1) vs (408/19/15/8), P=0.012] and urinary tract infections [no/mild/medium/severe, (14/2/1/1) vs (423/23/2/2), P=0.005], operation time [(206.3±15.7) min vs (181.2±12.1) min, P< 0.001], postoperative drainage volume [(330.2±53.5) ml vs (292.3±48.6) ml, P<0.001] and drainage time [(2.4±0.5) days vs (2.0±0.4) days, P< 0.001], whereas the former was significantly lower than the latter regarding the preoperative hemoglobin [(135.2±7.4) g/L vs (139.6±8.6) g/L, P=0.008] and albumin [(36.0±3.1) g/L vs (40.4±3.10) g/L, P=0.019]. As results of multivariate logistic regression analysis, the preoperative diabetes mellitus (OR=1.898, P=0.011), urinary tract infection (OR=1.612, P=0.027), and long drainage time (OR=1.426, P=0.015) were risk factors for early postoperative SSI, while the males (OR=0.811, P=0.038) and high albumin levels (OR=0.676, P=0.002) were protective factors for SSI. [Conclusion] Female, preoperative diabetes, urinary tract infection, hypoproteinemia and prolonged drainage time are risk factors for early SSI after posterior lumbar interbody fusion.