Abstract: This paper describes the main types of rock, colour, texture composition, structure characteristics,facies-indicaotors and terrestrial minerals, organism complex and their ecology,along with relative depths of water body,hydrod-namic condition, energy level, wave base, palaeogeomorphological featurcsy of sea bed, and geographical location in Nothwestern of Hunan province Correspondingly, the sedimentary environments of the strata from late Sinian to Ordovician are divided into eight types.