Based on a study of the lithologic association, vertical characteristics of sedimentary facies and regional sedimentary distribution of Amushan Formation in Manghanchaoke region, the authors hold that the flourishing period of Badanjilin marine rift basin was the sedimentary period of Amushan Formation. A study of geochemical indexes of kerogen carbon isotopes, the relative content of C27 -C29 sterane and saturation hydrocarbon characteristics shows that the main kerogen type is Ⅱ type. An analysis of original sedimentary environment with Pr/Ph shows that the main sedimentary environment was a reducing environment, which was beneficial for the preservation of organic matter. And the characteristics of vitrinite reflectance solid, maximum pyrolytic temperature and illite crystallinity show that the source rock owed its conversion into higly-mature to over-mature stage and mainly over-mature stage to the influence of tectonic dynamic activity and magma metamorphism of Late Variscan and Indo-Chinese epoch.