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The controlling factors of marine shale gas accumulation of south China are: (1) The well developed material basis of shale.The material basis of shale is the research on shale quality,includes shale lithology,thickness and distribution,geochemical parameters,physical parameters and mineral composition,the quality of which directly controlled gas content.The shale adsorption capacity and porosity reached their maximum range value when maturity (Ro) was between 1.1%~3.0%,and gas bearing capacity reaches a maximum value when maturity reached 2.3%.(2) Good cap rock and preservation condition.The different and uncertainty of the shale reformation leads to the differences of shale gas development even the same material basis of shale.It was suggested that the shale gas preservation conditions should studied by material basis,tectonism,evolutionary history,hydrogeology,seal and its microscopic properties,gas composition,pressure coefficient and other parameters of shale.(3) The favorable reservoir type.The most favorable reservoir type is organic matter micro-pores which decided by the complex tectonic.The micro-pores of the Longmaxi shale are mainly the organic matter micro-pores,while the micro-pores of the Niutitang shale are mainly the organic matter micro-pores and interparticle micro-pores,which determined the gas was adsorption state and the production curve was decreased slowly and smooth.(4) The certain degree of small and micro-fracture development.The giant and large fracture is not conducive to the development of shale gas reservoir,while the medium,small and micro-fracture (especially the horizontal fractures) is conducive to the development of shale gas reservoir.