The sedimentary facies in the Lower Cretaceous Nanxin Formation in the Yunlong region, western Yunnan, consist of meandering stream and lake facies with thin palaeosol facies. The meandering stream facies include channel, point bar, overbank, and natural levee subfacies, while the lake facies include littoral lake, shallow lake, and bathyal lake subfacies. The palaeosol facies are classified as calcareous soil and gley soil. These sedimentary facies indicate changes in regional tectonics from active to stable and subtropic semi-arid to arid palaeoclimates during the deposition of the Nanxin Formation.