Abstract: In order to avoid the existing bridge in the reconstruction and expansion of the bridge occurred in the old and new cross-beam position of the problem of mutual dislocation, the continuous T-shaped split-width beam bridge with asymmetrical spliced beams is taken as the research object, midas Civil was used to establish a finite element model, the reasonable splicing mode of splicing section beams is discussed, the mechanical characteristics and spatial force transfer mechanism of splicing wide beam bridges under vehicle load are analyzed. The results show that vehicle load has a great influence on the stress of T-beams of new and old bridges with different splicing girder types. As the number of beams at the splice is reduced from 9 to 7 and 5, the force transfer ability of the beams across the bridge is weakened, and the load transferred to the non-loading side is reduced. The bending moment and deflection of the T-beam at the non-loaded side, the secondary side span and the middle span are reduced. The bending moment and deflection of T-beam bridge with 7 transverse spacer beams vary little compared with the T-beam bridge with 9 transverse spacer beams, and the average variation amplitude is 3.59% and 2.69%, respectively. The stress and deflection of the T-beam bridge with 5 transverse separated beams have a large variation range, and the average variation amplitude is 16.96% and 10.31% respectively. When the time limit and funding, the use of 5 diaphragm splicing method.