The study of mechanical properties special in the characteristics of elastic element is a challenging task for vehicle industry. Since torsion bar spring acts as an important part of elastic element, and improves performance of torsion bar spring is of great concern. The effects of the torsion bar spring pre-setting precision on the presetting performance are presented. Based on elastic-plastic theories, the algebraic model of torsion bar spring is established to analyze the stress, torque and residual stress under the yield and plastic conditions in pre-setting process. Then, the stress and strain states of various torsion bar springs in different conditions are simulated using the validated finite element model in ABAQUS software. The simulation results show the effects of torsion error on the pre-setting performance are less than 5% in the pre-setting process. Compared to the pre-setting experiments data, finite element model and algebraic model of torsion bar spring are verified, and the results show that torsional performance can be ignored due to the torsion error in the range of ± 1°. The presented method is used to study the relationships between pre-setting conditions and mechanical properties accuracy of torsion bar springs. The research is expected to provide theoretical reference for establishing reasonable standards in pre-setting process.