With the rapid development of the Sino-Russian railway, in order to study the influence of track lateral irregularities on the deformation of seamless turnouts in alpine regions, a nonlinear finite element model of the spatial track frame was established to study the influence of track lateral irregularities on the stability of seamless turnouts. By setting parameters, the effects of temperature changes, lateral irregularities in the switch part, and lateral irregularities in the guide curve on the stability of the seamless turnout are studied. The results show that the greater the temperature change, the greater the lateral displacement. By comparing various working conditions, it can be concluded that when the curved rail of the guide curve part has lateral deviation, the seamless turnout will have a large lateral deformation, and the lateral displacement of the straight basic rail has a more obvious increase.