Abstract:  On the basis of the theoretical framework of breakage mechanics for geo-material,the fissured loess can be regarded as a composite material consisting of bonded blocks and weakened bands,therefore,a fissured loess binary-medium model is formulated.Then the model will be applied to the study of fissured loess.By numerical calculation,the relationship of stress-strain can be obtained.A comparative analysis between the calculated results and triaxial tests is done.The results show that there is a good adaptability to apply the binary medium model to fissured loess.