The sedimentary characteristics of marine source rocks discovered in recent years are generalized. As the aspects of the paleokarstic reservoir bodies，and the phrases and models of hydrocarbon accumulation，the progress on the theory of hydrocarbon accumulation in Paleozoic marine carbonate rocks is summed up and a new thought about available carbonate source rocks is suggested. A case of accumulation phrase of Ordovician hydrocarbon in Tahe Field is exampled and analyzed.