Aiming at the problems currently existing in the teaching of the curriculum of design of steel structure principle, this article conducted teaching reform exploration and practice of the "combination of three requirements, research on three levels, setting up the second classroom, construction of two platforms, and implement of two improvements". Namely, textbook compilation is carried according to three requirements of industry development, practical application, and the students' study. Study three levels of teaching and appraisal method on cases, tasks and projects. Second classroom jointing with steel structure enterprises was opened. Scientific research innovation and online teaching platforms was constructed in order to improve teaching efficiency and quality and students' comprehensive application ability, innovation ability and learning ability, and to realize the practical talents cultivation target.