Abstract: The cluster analysis method has been applied in a comprehensive study to investigate the sedimentary environment of the Upper Carboniferous Dalaian to the Lower Permian Longlinian of the Zongdi section, Guizhou Province, Southwest China, based on the statistic materials by microscope and referring to the observation in the field. Results of analyses show that there are 11 microfacies in the Zongdi section, namely, deep restricted lagoon, shallow restricted lagoon, deep alga mound, depression near shallow beach, shallow beach of platform margin, deep lagoon, shallow alga mound, shallow lagoon or tidal flat, tidal bar, restricted shallow beach or lagoon and deep slope. The assemblages and distribution patterns of the microfacies in the section demonstrate that the sedimentary environments during the Upper Carboniferous Dalaian to the Lower Permian Longlinian experienced 6 basic processes, namely, shallow beach, open platform, alga mound, restricted platform, deep slope and restricted mound.