This paper first considers the seismic parameter model of rail vehicles with rail constraints and investigates the mechanism of beam-rail interaction under earthquake action. The computational parameters of rails, main girders, and piers are optimized using analytical and finite element methods during earthquake action. Finally, the NSGA-II genetic algorithm is improved and applied to optimize the seismic parameters of rail vehicles, and seismic damage indexes evaluate the damage to rails and vehicles. The results show that by optimizing the seismic parameters of rail vehicles, the track damage is lower than the median value of μ [μ1 = 1.03404, μ2= 1.2013] under the same earthquake intensity, and the probability of lateral damage to vehicles is reduced by 0.15. Applying the improved genetic algorithm proposed in this paper can effectively improve the seismic performance of rail vehicles and provide some theoretical support for the design and safety of rail vehicles.