There are various genetic types of natural gas in eastern China, which are mainly of biogenic gas, abiogenic alkane gas and abiogenic CO2. Large biogenic gas fields discovered at present are mainly distributed in Ying-Qiong basin (Ya13-1, Ledong22-1, Dongfang1-1), Pearl River Mouth basin (Panyu30-1),Eastern China Sea basin (Chunxiao gas field) and Taixi basin (Tiezhanshan gas field) in the continental shelf, and carbon isotope of ethane is heavier than -28 parts per thousand, which shows that the gas is coal-derived. Large abiogenic alkane gas fields are distributed in the deep part of Songliao basin (Xingcheng gas field, etc), and the natural gas is characterized by heavy isotope (delta C-13(1)>-30 parts per thousand), negative carbon isotope series and R/Ra>0.5. CO2 gas fields distribute widely from Songliao basin in the north to Ying-Qiong basin in the south, and total 35 CO2 gas fields have been discovered in these areas with CO2 content more than 60% and d(13)C(CO2) heavier than -28 parts per thousand.