Abstract: In this paper, an approach to research on soils classification is developed, and a recommendation is presented for the soils classification system in Foundation Design Code of China.It is indicated by large amount of experimental data that the pseudo-plasticity phenomenon often appears in soil of low-plasticity. Based on the hypothesis of pseudo-plasticity, the writers have found that there exists a transitional type of soils, which can be called silt, with their characteristics quite different from sandy and clayey soils.The writers suggest that the soils cantaining less than 50% of particles which are coarse than 0.074mm should be defined as silt.The plasticity index of silt is in general less than 10, but whether Atterberg limits can be used as indices for such soils is doubtful.