Quantities of stochastic walking curves are generated with Monte-Carlo method, and 1 000 root-mean-square acceleration response spectrum in the vertical vibration direction of the test floor is calculated. Actual projects are studied to verify the results using response-spectrum method, and three cases of floor construction are adopted in this paper. The results of the measuring points using response-spectrum method are compared with other measuring values under the most unfavorable conditions and the theoretical values calculated by finite element method, which are all consistent. The method is helpful to obtain the position of response and to discover the main vibration mode which causes the structural maximum response, and it is also useful for the structural vibration control. The suggested spectrum-based approach can be used for the acceleration response of large span floor under a stochastic walking load.