Understanding the response of sedimentological processes to climatic aridification is crucial for deciphering climate signals preserved in the geological record. In this study, the well-exposed Middle Jurassic Shaximiao Formation of the Zigui Basin, western Hubei Province, China is interpreted as representing a typical suite of dryland fluvial deposits, based on detailed sedimentological features, together with the morphologies and geochemistry of diverse contained paleosols. Thirteen lithofacies have been recognized, which are categorized into four associations, including channel-bar deposits (FA1), unconfined fluvial flow deposits (FA2), heterolithicdominated deposits (FA3), and floodplain deposits with extensive paleosols (FA4). These associations are interpreted as representing two different phases of deposition, that is, a high-runoff phase characterized by vertically stacked, laterally migrating channels, and a low-runoff phase, with ephemeral channels. Cyclical climatic wet-dry conditions, high evaporative environments, and high carbonate enrichment are indicated by the abundant Calcisols, which represent the primary soil inorganic carbon pool in dryland settings. By combining our new data and previous studies, it seems that the transition from humid to arid zones in southern South China (central Yunnan) had occurred earlier than in northern part (Sichuan and western Hubei). This means that there was a northward aridification trend in South China during the Early to Middle Jurassic periods, and it is proposed that the dynamic migration of the Subtropical High-Pressure Belt might be a plausible mechanism for this gradual transition.