Abstract: The unification of data coding determines the efficiency of BIM data transmission and the quality of integrated delivery. By comparing different coding types such as Omniclass and KKS, a mapping rule between Omniclass and KKS coding is proposed. Three classification standards for water resources engineering are presented, namely the construction entities by function, spaces by function and elements by function, which are extended to the BIM information classification of the life cycle in water resources engineering. A new BIM unique coding structure based on Omniclass classification technology is proposed as the generalized and simplified generalized definitions are used. The practice flow, storage and exchange mode of the BIM unique coding structure for the water resources engineering are proposed. Taking a typical pump and sluice project as an example, the Bentley platform is used to load the new unique coding for the model, and the integral model coding is exported for data storage and exchange. By referring Cobie standard, taking the BIM unique coding as the core traction function and the level of detail（LOD）for information model as the framework data template, we can serve the BIM management platforms of water resources engineering and the integration delivery of BIM data.