Stress and strain analysis in lifted segments has been a prominent subject, especially with the increasing use of thin plates and higher pre-outfitting rates, which has brought to light the previously overlooked issue of torsional deformation. This research focused on investigating the mechanics of torsional deformation in thin-plate open-section segments with nonuniform weight distributions during lifting. By simulating the effect of the pre-outfitting weight using offset weights, establishing reasonable lifting point constraints, and creating a typical segment lifting analysis model, the results obtained through nonlinear and linear finite element analyses were compared. Extensive data was employed to establish the relationship between the torsional deformation and offset weights, using the principle of energy and the linear regression method. This analysis uncovered substantial disparities between the linear and nonlinear methods, with the linear approach failing to provide accurate stress and strain for torsion. Furthermore, the stress distribution obtained from nonlinear finite element analysis adhered to contemporary torsional theory. This paper underscores the nonlinear nature of torsional deformation, elucidates the influence of the weight distribution, and establishes a functional relation between the torsional deformation and offset weights, offering a robust tool for optimizing outfitting design and construction schemes.