Purpose <p>To analyze and compare the fusion effect and clinical effect of modified bone graft and conventional bone graft in lateral lumbar interbody fusion.</p> Methods <p>A retrospective analysis was performed on patients with lumbar degenerative diseases who underwent lateral lumbar interbody fusion in our department from January 2020 to February 2023. According to the different bone grafting methods, the patients were divided into modified bone graft group and conventional bone graft group. Evaluation of preoperative and postoperative ODI and VAS scores. The height of intervertebral space, interbody fusion, the formation of lateral bone bridge and the subsidence of fusion cage were evaluated after operation.</p> Results <p>Finally, 122 patients were included, including 56 in the modified bone graft group and 66 in the conventional bone graft group. The VAS score and ODI in the two groups were significantly improved after operation.After operation, the interbody fusion rate and the rate of lateral bridging callus outside cages (LBC) in the modified bone graft group were higher than those in the conventional bone graft group. The subsidence of cage in the modified bone graft group was significantly lower than that in the conventional bone graft group.</p> Conclusions <p>The improved method of bone grafting can significantly improve the formation rate of lateral bridging callus outside cages and the rate of interbody fusion, so as to reduce the complications caused by interbody fusion. Forming an intervertebral bone bridge as soon as possible is helpful to reduce the occurrence of intervertebral fusion cage subsidence.</p>