Abstract: Based on the concept of geo-binary medium model, a strength criterion for structured soils is proposed in the paper. The geotechnical characteristics of structured soils and remoulded soils are distinct in many aspects, without the exception of strength evolution rules. The strength criterions established already are formulated on the basis of the properties of reconstituted or remoulded soils, which can not reflect the influence of soil structures (bonding and fabric) on the properties of structured soils. After the strength evolution rules and mechanisms of structured soils analyzed through the many strength tests on the structured soils, the strength criterion for structured soils can be established by means of the concept of geo-binary medium model considering the breakage mechanism of geomaterials. The parameter of shear resistance share ratio is introduced and the determination of the parameter is also presented. By making comparisons between the data predicted by the criterion and the experimental data from two structured soils, Lacustrine clay and Louis clay, it is demonstrated that the new strength criterion provides satisfactory qualitative and quantitative modeling of the shear strength features of structured soils.