The author analyzed characteristics of the biological marker of Sinian and Lower-Palaeozoic mudstone and bitumen in the typical structural belt in the middle and southeast of the Sichuan basin.It is suggested that sedimentary environment of source rock was mainly reduction one with a certain extent of salinity,and organism was mainly sclerotia-algal from lower-class aquatic Organism.The reservoir Sinian-Lower Palaeozoic bitumen in the middle of Sichuan basin is Cambrian mudstone and reservoir bitumen in the southeast mixing source of Cambrian and Silurian mudstone.The paper analyzed the hydrocarbon-generation history of well Gaoke 1 using Karweil method,and modeled the hydrocarbon-generation history of well Dingshan 1 taking the method of apatite fission track and Easy%Ro.The comparative analysis indicated that maturity of Cambrian source rocks and oil-generation and gas-generation in the southeast Sichuan basin is earlier than the Middle-Sinian hydrocarbon source in the central part of the Sichuan basin.