Purpose To verify the parameters of thoracic and pelvic compensation and the criteria for initiating compensation during lumbar degeneration in different pelvic incidence (PI) populations. Methods A total of 625 asymptomatic adult volunteers were enrolled. Radiographic parameters, including the PI, C2-7 angle (C2-7), T1 slope, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), and sagittal vertical axis (SVA), were measured via standing lateral whole-spine radiographs. Those with a PI of 50 degrees or greater are classified into the high-PI group, and those with a PI of less than 50 degrees are classified into the low-PI group. Results A total of 332 patients were categorized into the low-PI group, and 293 patients were categorized into the high-PI group. In the low-PI group, PI-LL increases by 10 degrees, TK/PI decreases by 0.13, and PT/PI increases by 0.10. In the high-PI group, PI-LL increases by 10 degrees, TK/PI decreases by 0.12, and PT/PI increases by 0.09. ROC curve analysis revealed that TK/PI and PT/PI had good discriminative power for distinguishing loss of LL in the low-PI group (cutoff values = 0.714 and 0.318, respectively) and in the high-PI group (cutoff values = 0.599 and 0.370, respectively). Conclusions With the loss of LL, the PI-LL increases, the TK/PI decreases, and the PT/PI increases due to the occurrence of thoracic and pelvic compensation. The cutoff values of TK/PI and PT/PI can be used to determine whether compensation had occurred in patients with different PIs.