'Basic Principles of Steel Structures' is a basic professional course in civil engineering. The steel structure is one of the basic structural forms of modern civil engineering and widely uses in building construction, bridges, tower masts, offshore platforms, gas tanks, and oil tanks. This course bases on the nearly two decades of teaching experience of 'Steel Structure' of the Civil Engineering Specialty of Chang'an University. It focuses on establishing the basic concepts of steel structures and explaining the basic principles of steel structures. The new version of 'Standard for design of steel structure' GB50017 is used to build the bridge from mechanics principles to engineering design. The online course has a total of six chapters and about 200 minutes.