Abstract: With the development of science and technology, modern architectural technology has achieved great progress. A large number of large-scale buildings with beautiful shapes and unique structural forms have sprung up, which not only brings convenience to people's lives, but also endows people with the pursuit of architectural aesthetics. However, the wide application of special-shaped structure architecture design also brings the problems of complicated design and difficult construction. Taking the Chang'an Bridge Project as an example, the author expounds how to deepen the construction of special-shaped and complicated projects efficiently by using forward 3D design technology, which lays a solid foundation for the application of construction simulation analysis, 3D scanning and acceptance technology in this project. The problem of constructability of the special-shaped structure of Chang'an Bridge has been solved, which accumulates experiences for the application of forward modeling of engineering.