Abstract: Objective To compare the curative effect and prognosis of patients with single segment lumbar degenerative disease of different body mass index (BMI) undergoing posterolateral spinal 360° fusion. Methods A total of 216 patients with single segment lumbar degenerative disease admitted to the hospital from January 2013 to November 2017 were divided into normal group (84 cases, BMI less than 24 kg/m²), overweight group (80 cases, 24 kg/m² not less than BMI less than 28 kg/m²) and obesity group (52 cases, BMI not less than 28 kg/m²) according to different BMI. All patients underwent posterolateral spinal 360° fusion. The surgery-related data, the scores of Japanese orthopaedic association's low back pain assessment (JOA) and oswestry disability index evaluation system (ODI) at each follow-up time before and after surgery of the three groups were obtained. Results Arranging the intraoperative blood loss and postoperative drainage from small to large, the corresponding order was normal group, overweight group and obesity group. Arranging the operation time and postoperative hospital stay from short to long, the corresponding order was normal group, overweight group and obesity group. Arranging the incidence of wound complication from low to high, the corresponding order was normal group, overweight group and obesity group. The above indicators in each group were statistically significant (all P<0.05). The JOA score and ODI score of the three groups at each follow-up time after surgery were significantly improved compared with those before surgery (all P<0.05). There was no significant difference in the improvement of JOA score and ODI score between 1 month and 3 months after surgery (all P>0.05). The JOA scores in the normal group and overweight group were significantly higher than those in the obesity group at 6 months and 12 months after surgery, while the ODI score was significantly lower than that in the obesity group (all P<0.05). Conclusion Posterolateral spinal 360° fusion in the treatment of single segment lumbar degenerative disease can achieve good curative effect. The intraoperative blood loss and postoperative drainage are more in overweight or obese patients. The operation time and postoperative hospital stay are longer. And the incidence of wound complications is higher. Especially, the prognosis in obese patients is relatively poorer.