Soil mass is a mixture, including solid phase(soil grain), liquid phase(water), gas phase(gas), and involving three phases multicoupling interactions, so this situation decides soil mechanics relative lower development level and multichannel knowledge systems coming from other concerning subjects at present. In spite of this, effective stress principle, which makes separate concepts, knowledge points, and different theories connected together successfully, plays a key role during soil mechanics teaching practices for under graduate and post graduate students.Soil mechanics textbook knowledge system, as a matter of fact, is a continuous process covering understanding, explanation, and application of the effective stress principle in geotechnical engineering practices. Thus, further deepening understanding the effective stress principle is a very key issue about improving soil mechanics teaching quality for students.