Abstract: Fissured loess is regarded as a heterogeneous soil consisting of bonded blocks and weakened bands. The process of deformation failure of the fissured loess is the deformation, breakage and connection of the bonded blocks and weakened bands in loess. A double-parameter binary-medium model for fissured loess is proposed based on the breakage mechanics and is used to predict the behaviors of the fissured loess in triaxial shear tests. The comparison between prediction and experimental data demonstrates that the proposed model can satisfactorily simulate different deformation phases and reflect the brittle breakage and strain softening of the fissured loess.