Marine shale gas in southern China is characterized by high thermal evolution and tectonic movements. Based on the development and exploration of shale gas in southern China, this study proposed a preferential method that takes the preservation condition as the core and the geological evaluation as an emphasis, coupled with consideration of economic evaluation. This method screened out some key evaluation index, such as total organic carbon (TOC) content and thermal maturity and pressure coefficient, which are suitable for evaluating favorable areas of shale gas in southern China. TOC content is the material basis for shale gas enrichment and accumulation; thus selecting favorable area should be the shale formation with high TOC content (TOC>2%) in thick shale section. Excessive maturity has a negative impact on shale gas enrichment and accumulation, and selecting favorable area should be on the basis of “finding a low R o value in high place”, ie. looking for the areas with high pressure coefficient in the intensive tectonic setting. Pressure coefficient can directly reflect the preservation degree of shale gas, and the higher the pressure coefficient indicated the better preservation degree of shale gas. Taking the exploration of shale gas in the Niutitang Formation in northwestern Hunan Province as an example, it is believed that the Niutitang shale gas has good prospects for exploration and development, but the high thermal maturity and poor preservation conditions (low pressure coefficient) are the major risks for enrichment and high yield of shale gas in northwestern Hunan Province.