The Devonian period is a significant geological time marked by widespread deposition of organic- matter- rich shales. Within an inter- platform basin facies dominated by deep- water deposits in the region from southern Guizhou to central Guxngxi, a remarkable accumulation of organic- matter- rich tentaculitid shales exceeding 600 meters in thickness developed during the Emsian to Frasnian ages. These shales exhibit characteristics that make them a potential target for shale- gas exploration: ① Relatively higher total organic carbon (TOC) values consistently exceed 2%~4%, reaching up to 5% to 6%. ② During the early to middle Devonian (Amsian Age), organic carbon content is typically enriched in massive organic- matter- rich tentaculitid shales with the monolayer thickness exceeding 100 meters, formed during periods of third- order relative sea- level rise. Conversely, calcareous shales and muddy limestones of the shelf facies, formed during sea- level falls, exhibit depleted organic carbon content. ③ Within the Frasnian Age Liujiang Formation, dominated by silicalites, organic carbon content is typically enriched in massive organic- matter- rich tentaculitid sales with the monolayer ranging from 30 to 40 m thick, formed during the periods of third- order sea- level fall. This contrasts with silicalites of the pelagic basin facies, which show lower organic carbon content during periods of third- order relative sea- level rise. The accumulation of organic matter in these tentaculitid shales is controlled by complicated, nonlinear interactions between productivity, preservation, and sedimentation rates. Importantly, the high density of tentaculitid fossils demonstrates that the accumulation of organic matter within organic- matter- rich tentaculitid shales is genetically related to the biological carbon pump of zooplankton.