The rainflow cycle counting is carried out on seventeen random processes of band-limited white noise with different band widths, and a probability density function(PDF) model of rainflow amplitude for random processes of band-limited white noise is proposed. This model is a linear combination of a Rayleigh distribution and a Weibull distribution, where the undetermined coefficients are all functions of the spectral parameters of the random process. Data fitting is carried out on the rainflow amplitude PDFs of the seventeen random processes based on the proposed model, and the relationship between the parameters in the model and the spectral parameters of the random processes are investigated, and the formula of the model is determined. According to the rainflow cycle counting results of the random processes, the prediction accuracy of the proposed model is compared with that of Dirlik’s model, which shows that the proposed model gives better prediction results than Dirlik’s model.