For light and long-span structures, human-induced vibration may present a serviceability issue. To study the vibration serviceability problem, it is important to have a better understanding on human-induced forces, such as walking. To this end, the load-time histories of walking excited by 25 test participants were measured using a force-measuring plate. Totally, 300 walking force–time histories were recorded; and the peak load factors were compared in detail. The correlation analysis shows that there is a weak correlation between the three directional components of walking load, i.e., the walking component can be modeled independently. Then, the Fourier series functions for walking were derived; and the relationships between the dynamic loading factors, phase angles and the duration time Tp of single-step walking were developed, giving the forcing functions. The load-time history extension method was used to establish the forcing function for continuous walk. Lastly, the proposed continuous walking model was validated with the test and finite element results.