Objective To investigate the influence of spinal cord decompression on posterior surgical treatment of thoracolumbar fracture, and to provide the practical basis for the indications of posterior spinal cord decompression Methods The cl inical data were retrospectively analyzed from 170 cases of thoracolumbar fracture treated with posterior surgical treatment between January 2005 and January 2009. There were 119 males and 51 females with an average age of42.7 years (range, 17-68 years). The fracture locations included T11 in 22 cases, T12 in 30 cases, L1 in 57 cases, and L2 in 61 cases. According to Denis classification system, there were 65 cases of compression fractures, 44 cases of burst fractures, 25 cases of flexion-distraction injuries, and 36 cases of fracture-dislocations. The time from injury to operation was 3-8 days (mean, 4.4 days). All the cases were divided into 4 groups according to space-occupying rates of spinal cord: group A, ≤20% (n=32); group B, 21%-40% (n=68); group C, 41%-60% (n=37); and group D, ≥ 61% (n=33). Through statistical analysis, the correlation between space-occupying rates and spinal cord function (Frankel grade) was evaluated, and the necessities of spinal cord decompression was studied in the patients who had neurological symptoms with space-occupying rates under 40%. Results There was no positive correlation between the degree of spinal cord injury and the space-occupying rates of bone fragments broken into the spinal canal. All patients were followed up 13-41 months (mean, 23.5 months). During the follow-up period, no secondary neurological damage occurred in the patients who were not given posterior spinal cord decompression with space-occupying rates under 40% (28 cases). And also in the cohort of patients with neurological symptoms whose space-occupying rates were under 40%, the posterior spinal cord decompression (65 cases) could improve the spinal cord function significantly when compared with no decompression cohort (7 cases), (P lt; 0.05). Conclusion The relative indications of posterior spinal cord decompression for thoracolumbar fracture are as follows: the cases having neurological symptoms with space-occupying rates under 40% and the ones having the neurological symptoms or not with space-occupying rates above 40%.