Abstract: At present,fixed PV brackets are mainly divided into two types,that is rigid PV brackets and flexible PV brackets. Rigid PV brackets are usually supported diagonally to bear the load of PV modules,while flexible PV brackets mainly bear the load of their upper PV modules through prestressed steel cables.The commonly used flexible and rigid PV brackets have the problem of small one pile covered area,so when deploying PV modules of a certain area,a larger number of piles are required;When using pile driving methods or when the cost of a pile is high（such as driving piles for large-span structures over the sea）,the overall economy is poor. Based on the challenges brought by inconvenient water construction of PV support structures,this paper proposes a modular large-span water PV support system scheme. Taking a PV power generation project as an example,economic calculations show that this scheme can effectively reduce the number of lower piles used,thereby reducing costs. In addition,the supporting components and construction plan also enable the PV support system to achieve modular construction,thereby reducing the difficulty of offshore operations and improving construction efficiency.