The paper provides a model of continuous walking load in the vertical direction based on the available measured force-time histories induced by a single foot of an individual walking. The characteristics and models of people walking are examined and all the parameters defining the load model, including walking velocity and frequency, Fourier coefficients and phase lags, are investigated. The velocity and frequency of people walking are determined from site survey and the relation between walking velocity and frequency are introduced. The available measured force-time histories of four types of walking (normal, brisk, slow and fast) are digitised and expressed by polynomials. The forces produced by two adjacent foot steps are combined based on the principle that the integration of walking force in a period is equal to the product of the period and the weight of the walker. Fourier integration is used to determine the first six Fourier coefficients and phase lags. The load models of the four types walking are assessed. It is concluded that the normal walking of the four types of walking is suitable for the use in design and analysis.