In order to determine sedimentary characteristics and model of the late Early Silurian strata, the authors comprehensively studied outcrop sedimentary features and a large number of core and well logging data of the Silurian Xiaoheba Formation. The results show that the late Early Silurian transitional sedimentary system group and marine sedimentary system group are developed in the southeastern Sichuan Province and include three kinds of sedimentary facies and lots of sub-facies as well as micro-facies. The new understanding has an important theoretical and practical significance for more accurately predicting the distribution of the sandstone of Xiaoheba Formation in the southeastern Sichuan Province.