The evaluation and optimization of the target layer of shale gas are the emphases in the early stage of research of shale gas exploration. Shale is not only the hydrocarbon source bed but also reservoir. A set of technical method which can be used to accurately and rapidly evaluate shale is the key of the research. Through the practice of shale gas exploration study in Lower Yangtze area,“two layer and six terminal element” shale evaluation method was proposed. By optimizing parameters that can reflect shale hydrocarbon generation potential and reservoir performance, we drawn up quantitative evaluation criterion of all parameters, then used “two layer and six terminal element” diagram to diagrammatize, classify and evaluate shale semiquantitatively. The method has great systematization and operability. This method was applied to comprehensively evaluate four sets of Paleozoic shale developed in the west of Lower Yangtze area. Lower Permian Gufeng Formation and Upper Permian Dalong Formation have good hydrocarbon source condition and reservoir properties of shale, and these two formations are the main target layers for the shale gas exploration.