Objective: To investigate the characteristics and significance of spinal-pelvic sagittal parameters in elderly patients with post-traumatic thoracolumbar kyphosis (PTK). Methods: A retrospective study of the clinical data of single-segment elderly PTK patients (PTK group, 65 cases) and simple osteoporosis (OP) patients (OP group, 50 cases) diagnosed and treated in our hospital from January 2018 to December 2020. Compare the thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), pelvic projection (PI), sacral slope (SS), pelvic tilt (PT), and sagittal vertical axis (SVA) between the two groups of patients, and analyze the correlation between the parameters in the PTK group. Results: Comparison of PI between the two groups showed no significant difference (P >0.05). TK, TLK, PT and SVA in the PTK group were greater than those in the OP group (P <0.05). The LL and SS of the PTK group were smaller than those of the OP group (P <0.05). The imbalance rate of PTK group (53.85%) was significantly higher than that of OP group (20.00%) (P <0.05). In the PTK group, TK was related to TLK and SVA (P <0.05), and PI was related to PT and SS (P <0.05). Conclusions: PTK patients with spine-pelvic sagittal parameters the correlation change, sagittal imbalance is prone to occur, the center of gravity moves forward, resulting in posterior pelvic rotation.