Overhead crane not only can lifts parts of workshop or steels in factory, but also lifts bulk cargo with professional lifting tools, such as coal and ore etc. The mostly factories adopt double girder overhead crane in China; it is suitable for lifting and transferring of goods which more than 20t. The main girder of overhead crane adopts double box beams; it can meet the requirements of strength, rigidity and stability of big tonnage crane. The traveling speed of crane is quick, and production efficiency is high. Different lifting tools can meet the lifting and installing requirements of different situation.