Abstract: To promote the research and application of quantitative classification of soils in Guizhou, based on analysis data of 185 representative soil profiles obtained from soil investigation in Guizhou from 2015 to 2017, combined with previous soil survey data in Guizhou, we carried out a comprehensive analysis of soil formation characteristics, identification of soil diagnostic horizons and diagnostic characteristics and the category division of system classification advanced unit. The results showed that: desilication and allitization of soils in hilly and mountain areas of Guizhou were mainly moderate to weak, and the accumulation of soil organic matter and soil humic property were obvious; the ferric property and alic property were more frequent in the soils; and the soil claying, soil yellowing, and lithologic characters of carbonate rocks were more common; human activities had an obvious influence on the soil evolution. The main soil temperature regimes in Guizhou were thermic and mesic. There were 5 kinds of soil moisture regimes in Guizhou, incluing udic, perudic, stagnic, anthrostagnic, aquic. According to the keys to Chinese Soil Taxonomy (3rd edition), 8 soil orders, including Histosols, Anthrosols, Gleysols, Isohumosols, Ferrosols, Argosols, Cambosols, and Primosols were identified. There were 16 soil suborders, 41 soil groups, and 86 soil subgroups in Guizhou. We analyzed soil forming environment of main soil orders of Guizhou, compared the soil classification units in Guizhou between Chinese soil taxonomy and geographico- genetic classification of China, and put forward a suggestion for adding 3 subgroups of anthrostagnic hapli-stagnic Gleyosols, anthrostagnic molli-orthic Gleyosols, and anthrostagnic hapli-orthic Gleyosols in Gleyosols order of the Chinese soil taxonomy.