To investigate the effect of closure jacking force on the mechanical performance and displacement of long-span continuous rigid frame bridges, a large-span continuous rigid frame bridge project in Xiangxi Prefecture, Hunan Province was used as an example. With the closure jacking force coefficient as the unknown variable, stress at the base section of the pier as the constraint condition, and the minimization of the sum of squared horizontal displacements at the pier top as the objective, the closure jacking force for the continuous rigid frame bridge during closure was determined. Using Midas Civil finite element software, numerical models of the continuous rigid frame bridge were established for both scenarios: closure with and without jacking force. The study analyzed and compared the effects of these two closure scenarios on the stress of the main beam, vertical displacement, pier top horizontal displacement, and base stress after 10 years of constant load. The research also analyzed the impact of temperature difference during closure on the pier top horizontal displacement and derived the relationship between jacking force and closure temperature difference. The results showed that the top pushing closure construction method effectively improved the mid-span deflection caused by concrete shrinkage and creep, reduced the longitudinal bridge horizontal displacement at the pier top, improved stress distribution at the base, and had a relatively minor impact on main beam stress.