Online and offline mixed teaching activities provide important thought for efficient teaching and study of professional courses under public emergency conditions. Considering the integration path of college education and online teaching, aimed to the online process of professional courses for geotechnical engineering, some problems are researched, such as the significant differences in shared teaching resources, single teaching process, consumption of dissolution and reconstruction of teacher-student relationship, and mismatch of teaching hardware. Thus, corresponding teaching design has been proposed related to the systematical online teaching process, optimization of teaching content keeping pace with the times, diversification of teaching mode, multiple arrangement of student assignments, and process-oriented implementation of examinations, to realize the diversified operation of online teaching mode, improve students’ autonomous learning ability, establish diversified examination and assessment methods, and promote the effect of online teaching. All the above achievements can be significant guidance for universities’ large-scale open teaching activities under the public emergency conditions.