Abstract: In this paper, taking Daliangshan region of Sichuan Province as a case study, the authors put forward the classification of soil parent materials based on geological formation, which takes the tectonic evolution and geological formation environment as foundation, and combines with the genetic type of eluvium and slope deposit. The soil parent materials in Daliangshan region are classified into 12 types, including Quaternary alluvial-diluvial deposit, Neogene-Quaternary sandstone and mudstone eluvium and slope deposit, Jurassic-Cretaceous mudstone eluvium and slope deposit, Triassic sandstone and mudstone eluvium and slope deposit, Jurassic-Cretaceous acidic magmatic eluvium and slope deposit, Triassic intermediate-acidic magmatic eluvium and slope deposit, Permian basic-ultrabasic eluvium and slope deposit, Sinian-Triassic sandstone and mudstone eluvium and slope deposit, Sinian-Triassic carbonate eluvium and slope deposit, Proterozoic intermediate-acidic eluvium and slope deposit, Proterozoic basic-ultrabasic eluvium and slope deposit, and Proterozoic metamorphic eluvium and slope deposit. The results show that there are differences between parent material and soil, While different soil types of same parent material have similar geochemical characteristics, and same soil types of different parent material have different geochemical characteristics. Therefore, the classification of soil parent materials based on geological formation can not only effectively reflect the difference of parent materials under diffe-rent tectonic setting and diagenetic environment, but also effectively present the internal relationship between pa-rent material and soil.