Soil mechanics is basic, timeliness and practical as a required course for geotechnical engineering. With the increase of the number of graduate students, the theoretical and professional nature of soil mechanics has put forward higher requirements for learning, so it is necessary for teaching exploration to expand on the basis of the existing course content. Based on the author"s teaching experience in soil mechanics, the chapter of "shear strength of soil" in soil mechanics and the chapter of "constitutive relation of soil" in advanced soil mechanics were connected. Focusing on introducing the critical state of soil, key points related to triaxial tests and soil properties were necessarily supplemented, and critical state analysis of sand soil was provided as an example. As a current hot issue, information about "microbially induced calcite precipitation" was given as a report. This paper introduced how to expand the study points of soil mechanics and how to introduce the subject frontiers. This helpt students understand and consolidate the basic theoretical knowledge, stimulate and cultivate students" interest and ability in independent learning, and create good basic conditions for further study.