The Lingdingyang Bridge in the Shenzhen-to-Zhongshan link is the world's largest full offshore suspension bridge with a main span of 1666m. In order to solve the construction problem of huge quantity of the lower crossbeam, the construction scheme of the bored pile support system is innovatively put forward, the design of which is detailly introduced in the article. The large-scale general finite element software is used to analyze the force of the bored pile support system. By the analysis, the distribution ratio of the upper concrete load between the lower concrete and the support system in the layered concrete structure is drawn up, and the safety of the structure is verified. The application shows that the use of bored pile support system to construct the lower crossbeam with huge quantity has high safety and obvious economic effects, which can be used as a reference for other similar projects.