The understanding from the conventional geochemistry and geology analysis is very different when trying to apply them to shale gas plays. This paper is a summary for U.S. shale gas plays on geochemistry and geologic analysis application, and real field data from active U.S. shale gas plays is used in the discussion of different concepts. The understanding from the conventional geochemistry and geology analysis is very different when trying to apply them to shale gas plays. This paper is a summary for US shale gas plays on geochemistry and geologic analysis application, and real field data from active US shale gas plays is used in the discussion of different concepts.