Abstract: In this paper,the authors discussed the gas generating characteristics of marine shale and marl by hydropyrolysis.At the mature stage of organic matter,the total gas yield of marl was above that of shale,and their total gaseous hydrocarbon yield was approximately the same.The difference between their total gas yield increased with temperature,and the gaseous hydrocarbon yield of marl was above that of shale at higher temperature.The gas drying coefficient of marl was above that of shale and was below 0.55,and their gas drying coefficient tended to be the same at higher temperature.The normal alkane abundance was higher in shale than in marl,and was stronger than the isonormal alkane,s.Dioxide carbon,nitrogen and hydrogen were major,and oxide carbon was little among nonhydrocarbons.Dioxide carbon content in shale was above that in marl,and hydrogen content in shale was below that in marl.Nitrogen yield was higher at the early and middle mature stage,and was more in marl than in shale.