Objective To explore the effectiveness and related issues in the treatment of multiple segments of thoracolumbar tuberculosis through posterior unilateral debridement with bone graft and internal fixation. Methods The clinical data of 29 patients with multiple segments of thoracolumbar tuberculosis who met the selection criteria were retrospective analyzed between January 2012 and July 2015. There were 17 males and 12 females, with age of 21-62 years (mean, 37.4 years). Lesions contained 3-8 vertebral segments, including 3 segments in 6 cases, 4-6 segments in 17 cases, and 7-8 segments in 6 cases. The center lesions located at thoracic spine in 8 cases, lumbar spine in 10 cases, and thoracolumbar segment in 6 cases, and thoracic lumbar skip lesions in 5 cases. The complications included vertebral abscess in 7 cases, psoas major abscess in 6 cases, sacral spine muscle abscess in 7 cases, iliac fossa and the buttocks abscess in 1 case, spinal canal abscess in 2 cases. Preoperative neurological function was assessed according to the American Spinal Injury Association (ASIA) classification: 1 case of grade B, 3 cases of grade C, 8 cases of grade D, and 17 cases of grade E. The disease duration was 6-48 months (mean, 19.3 months). All the patients were treated with posterior unilateral transpedicular or transarticular debridement with bone graft fusion and internal fixation under general anesthesia. Pre- and post-operative visual analogue scale (VAS) score, Oswestry disability index (ODI), and sagittal Cobb angle were recorded and compared. Bridwell classification standard was used to evaluate bone graft fusion. According to the number and the center of the lesion, the necessity to placement of titanium mesh cage was analyzed. Results All the patients were followed up 18-30 months (mean, 24 months). Cerebrospinal fluid leakage occurred in 3 cases, intercostal neuralgia in 2 cases, wound unhealed and fistula formation in 1 case, and ofiliac fossa abscess recurred in 1 case, and all recovered after symptomatic treatment. During follow-up, no fracture or loosing of internal fixation was found and all the lesions were cured at last follow-up. According to Bridwell classification standard, bone graft achieved bony fusion during 4-9 months after operation. The VAS score, ODI, and Cobb angle at immediate after operation and at last follow-up were significantly improved when compared with preoperative ones (P<0.05). At last follow-up, the neural function of all patients improved significantly when compared with preoperative one (Z= –3.101, P=0.002). The ratio of no placement of titanium mesh cage was significantly higher in patients with more than 6 lesion segments (6/6, 100%) than in patients with less than 6 lesion segments (4/23, 17.4%) (χ2=14.374, P=0.000). And the ratio of placement of titanium mesh cage was not significantly different between the patients with the different locations of center focus (χ2=0.294, P=0.863). Conclusion For treating multiple segments of thoracolumbar tuberculosis, the method of posterior unilateral debridement with bone graft and internal fixation can decrease the damage of posterior spinal structures and surgical trauma.