In recent years, our country has actively promoted the transformation of construction industry and vigorously developed intelligent construction. However, the level of intelligent construction is still low in the construction process of large and complex steel structures, and the traditional construction method is not enough to solve the current engineering problems. Therefore, this paper proposes a BIM-based intelligent construction application system for large and complex steel structures. The system integrates a variety of modern technologies based on BIM technology, and builds a set of BIM-based full-stage information intelligent management system and specific application process throughout the three stages of design, construction and operation and maintenance, which can fundamentally tackle the difficulties encountered in the process of construction and management. Based on this system, this paper also constructs a set of intelligent construction application system for construction process. In the practice of China Electric Science and Electric Science and Technology Innovation Park, this set of intelligent construction system can solve the problems for technical management in the construction process of large and complex steel structures, assist the construction of intelligent sites, and promote the development of intelligent construction.