Abstract: The uneven deformation during the rolling of H-beam is primarily concentrated in the roughing stage of shaped pass rolling. The dimensional precision control in shaped pass rolling has a significant impact on the subsequent universal rolling process. To this end, the finite element analysis software MARC/SuperForm was utilized to simulate the opening rolling process of a shaped billet with dimensions of 900 mm × 510 mm × 130 mm. The key factors and influencing mechanisms of web thickness variation were analyzed. Based on the simulation results, the roughing rolling schedule for H-beam was optimized by adjusting the reduction distribution, specifically reducing the reduction in the web during the final pass, and minimizing the elongation difference between the web and flange,thereby reducing the degree of web thickening. The results indicate that the web thickness significantly increases near the exit of the deformation zone, with the web thickness at the end of roughing being 8.4 mm greater than the set thickness. This is primarily due to the difference in elongation between the web and flange. In the deformation zone, the web metal is subjected to triaxial compressive stress. When the workpiece exits the deformation zone, the pressure and transverse resistance from the rolls gradually disappear, but the rolling-direction pressure exerted by the flange on the web does not disappear immediately. The web continues to experience compressive stress in the rolling direction, leading to further thickening of the web. The elongation of the web is typically greater than that of the flange, especially under conditions of large reductions, resulting in significant elongation differences and substantial thickening of the web after exiting the deformation zone. By adopting the optimized roughing schedule for H-beam, the thickening of the web at the end of roughing rolling is reduced from the original 8.4 mm to 3.7 mm, effectively improving the dimensional accuracy of the web section.