The longitudinal change of track stiffness in the turnout area will cause longitudinal unevenness of the track, resulting in aggravated wheel-rail interaction, which will have an adverse impact on line safety and maintenance operations. Optimizing the stiffness of the track structure in the turnout area can greatly improve the driving smoothness of the line and extend the service life of components. For the No. 18 turnout, this paper established an adaptive optimization model for turnout stiffness homogenization based on genetic algorithm, and proposed a segmented stiffness homogenization scheme that adapts to operating conditions, which significantly improved the problem of large stiffness changes in the turnout area; by establishing a rigid-flexible coupling dynamic analysis model of the vehicle-turnout system, the dynamic improvement results of the train passing the turnout based on the genetic algorithm were studied. When the train passes through the turnout area, the wheel-rail lateral and vertical forces are significantly reduced, with a maximum amplitude of 10.15%, and the maximum reduction in the lateral and vertical acceleration of the vehicle body is 12.12%.