In the early 1960s, Prof. Shen proposed a theory of limit equilibrium for granular media by combining Sokolovski's static theory and Drucker-Shield's kinematic theory, and recommended the effective consolidation stress method for stability analysis of soft soils. Later, he was engaged in constitutive modeling of soils, putting forward many new concepts in soil plasticity, such as the multiple yielding surface, the equivalent stress hardening law and the triple shear stress yield criterion. He proposed two new constitutive models, developed the effective stress method for analysis of earth structures, and compiled six computer programs having wide application in the soil engineering in China. Recently, he has made a suggestion to develop a new type of soil model, named the structural model, to take into account the breakage of bonding between soil particles, and has proposed the duplex spring model by introducing a new mechanical element named the stuck-bar element. In the mean time, he proposed an idea to establish the basic framework of modern soil mechanics.