The organic inclusions in the Taibei Depression, Donghai (the East China Sea) Basin, are studied by LAM and perogenation Gc, with results as follows. ①CO2 is mainly component in the organic inclusions, which is 40%~78% in the gas hydrocarbon inclusions and 23%~41% in the liquid ones respectively, at the same time, there are some N2 and F2 . ②The component of hydrocarbon in the organic inclusions is <30%, in which, the CH4 is less, and the C2~C7 is more, the toluene is 18 8%. ③The same characteristics can be observed in the simulation experiment. The composition of organic inclusions shows that the origin of CO2 is related with the carbonate mineral in source rocks, original type of organic inclusions is III, the gas hydrocarbon is mainly humidity. All of these are similar to the organic inclusions in the Nanhai (the South China Sea) Basin.