The invention discloses a vertical suspension frequency design method for suspension equipment at the lower part of a high-speed train body, and the method comprises the steps: S1, obtaining the length and mass of a target train body and a first-order vertical bending modal frequency according to an obtained entity model of the target train body; S2, according to the length and mass of the targetvehicle body and the first-order vertical bending modal frequency, constructing equivalent Euler-Bernoulli beam elastomer model of the target vehicle body, , and obtaining a vibration mode function; S3, obtaining the position of the mass center of each under-vehicle device in the longitudinal direction of the vehicle body according to the under-vehicle device arrangement condition of the target vehicle body, and determining the function value of the first-order vertical bending modal shape of the vehicle body at the corresponding position according to the vibration mode function in the step S2; s4, according to the first-order vertical bending modal frequency of the vehicle body, determining the vertical suspension frequency, the static stiffness and the deflection of each under-vehicle device of the target vehicle body; and S5, connecting each piece of under-vehicle suspension equipment of the target vehicle body with the vehicle body to realize the optimal design of vertical suspension frequency, rigidity and deflection.