Abstract: The dual effective stresses of porous media were established in1999and have been widely applied nowadays. The concept of dual effective stresses was proposed after Terzaghi effective stress and Biot effective stress. Terzaghi effective stress is only applicable to extremely loose porous media approximately, and Biot effective stress is an empirical formula, which have some defects. The dual effective stresses overcome the defects of them by taking consideration of deformation mechanism and material structure of porous media. Porous media have two typical deformations: primary deformation and structural deformation. Correspondingly porous media have two effective stresses: primary effective stress and structural effective stress. Primary effective stress determines the primary deformation of porous media, while structural effective stress determines the structural deformation. By introducing parameters of material structure of porous media into the formula, the dual effective stresses unified porous media and common solids using porosity, so can get wider applications than Terzaghi effective stress and Biot effective stress.