I-beam has small side length and high height, and can only bear single direction force. H-shaped steel groove is deep and thick, which can bear the force in two directions. 2. I-beam can only be used for beams, while H-beam can be used for bearing columns of structures. 3. H-beam is a kind of economical section steel with better mechanical properties than I-beam. Its section shape is the same as the English letter "H". The flange of hot-rolled H-beam is wider than that of I-beam, with larger lateral rigidity and stronger bending resistance. Under the same specification, H-beam is lighter than I-beam. 4. The flange of I-beam is thick on the web with variable wearing surface and thin on the outside; the flange of H-beam is equal wearing surface. I-section steel, whether ordinary or light, has relatively high and narrow section size, so the moment of inertia of the two main sleeves of the section is quite different. Therefore, it can only be directly used for bending members in the plane of its web or forming lattice stress members. It is not suitable for the axial compression members or the members which are vertical to the web plane and bent, so it has a great limitation in the scope of application. H-section steel is a kind of high-efficiency and economic cutting profile (other are cold-formed thin-walled section steel, profiled steel plate, etc.), because of the reasonable section shape, they can make the steel more efficient and improve the cutting capacity. The flange of H-beam is widened, and the inner and outer surfaces are usually parallel, which makes it easy to connect with other members with high-strength bolts. Its size and structure are reasonable series, and its model is complete, which is convenient for design and selection. (except I-section steel for crane beam