Abstract: In order to support the geological investigation and research of hydrological engineering environment in the areas with complicated geological conditions, the authors analyzed systematically the lithology, architecture and structure of Quaternary strata in hilly plain areas of Wanjiang River Economic Zone. Taking the geomorphology, Quaternary genesis, sedimentary facies and sediment provenance as the indexes, combined with the existing regional Quaternary research achievements and the classification of chronostratigraphy and lithostratigraphy, the authors carried out the division of Quaternary geological units in hilly plain areas along Wanjiang River. The hilly plain areas were divided into three first-level geological units, namely, alluvial-lacustrine plain geological units, flood-slope hilly geological units and residual-denuded hilly geological units. Seven types of Quaternary stratigraphic structure combinations and their characteristics are summarized. This study can lay a foundation for regional hydrogeological and engineering geological survey and research.