Abstract: The thermal simulation tests of major source rock of five hydrocarbon-generation series including eight sets of hydrocarbon-generation layer/formation were made.The results showed that hydrocarbon-generation rate was controlled by kerogenic type and environment of source rock.hydrogen-enriched source rock has high hydrocarbon-generation rate and varied gas-generation rate ;hydrogen-enriched source rock in strong reducing environment can earlier enter oil generation threshold and generate low maturity oil.In addition, thermal fractionation effect occurred in simulated products (liquid and gaseous hydrocarbons)and kerogen with simulated temperature increasing in varying degrees ;evolution law of elements and functional group of kerogen reappeared with simulation test, and moreover, hence revealing hydrocarbon-generation mechanisms of different types of source rocks.Based on these, it is suggested that we should pay high attention to the Lower Cretaceous and Paleogene in west side of piedmont sag in south margin of Junggar basin, in which possess geochemical conditions of generating low maturity oil, in addition to continuing to find primary and secondary reservoi rs associated with Carboniferous-Permian source rock wi thin the basin and to find secondary reservoirs associated with Triassic-Jurassic source rocks in south margin of Junggar basin.

Key words: Junggar basin, Source bed, Gas source rock, Simulated test, Hydrocarbon yield, Oil and gas distribution, Exploration