Abstract: The excess pore pressure induced by seismic loading leads to soil liquefaction. Proper characterization of the pore pressure generation due to cyclic loadings is essential for liquefaction analysis of soils. The results of a series of undrained cyclic triaxial tests based on clean sand and silty sand with fines of 10% are introduced. The data are analyzed in the framework of two pore pressure models (uniform cyclic stress model and energy dissipation model). A new uniform cyclic stress model is proposed to better characterize the pore pressure generation, and the model parameters are calibrated. Meanwhile, a one-parameter energy dissipation model is calibrated and analyzed as well. It is found that the parameters of the uniform cyclic stress model are mainly affected by the amplitude of the stress cycles and mildly affected by the fines content, while the parameters of the energy dissipation model are mainly affected by the packing density and soil type.