In an inter-platform basin facies within the Dianqiangui Basin that was located in the southwestern part of the South-China plate, a set of organic-matter-rich shales with a total thickness of near 300 m and a total a relatively higher total organic carbon (TOC) value of more than 2%, i.e. the Luzhai Formation (Fm.), was centrally developed and formed in the relatively third-order sea-level rising period from the Tournaisian and the Visean Ages of the early Carboniferous, which makes up an importantly potential target rock for shale-gas exploration. A special forming time, a diachonism that is marked by a complex change to the Yingtang Fm. on the attached-platform setting through both the decrease of thickness and the facies changing, and an end with the development of a set of coal measure strata caused by delta sedimentation all characterize a particularly sedimentary succession of the early Carboniferous (the Missippissian) in the study area that was dominated by Luzhai Fm. with a great difference from the sedimentary succession on supercontinent of Pangaea. Actually, this great difference further reflected as the following fact, i.e. only the upper part of the Carboniferous System (the Pennsylvanian Subsystem) harbors enormous volumes of coal and the lower part (the Missippissian Subsystem) contains an unusually large proportion of limestone on Pangaea. The accumulation of organic matter within organic-matter-rich shales that made up the anoxic basin facies of the Lower Carboniferous in study area is generally tally with a fundamental and comprehensive model, i.e. accumulation of organicmatter is controlled by complicated interactions among the three factors: the enhanced productivity and the organic matter preservation, and the decreasing sedimentation rate that led to the weakening of dilution to organic mater, and all of which were directly affected by relative sea-level fluctuations. However, the accumulation of organic matter can not be excluded to the biological carbon pump especially for one of phytodetritus, although there are many detail problems need to further research.