Abstract: The over-mature kerogen samples from the northeast Sichuan Basin were studied by catalytic hydropyrolysis in a fixed-bed reactor.The products were analyzed with GC-MS and were compared with source rock extracts.The distribution features and geochemical information of sterane,terpane in saturate hydrocarbon and dibenzothiophene and fluorene in aromatic hydrocarbon were studied.According to parameters such as hopane index,Pr/Ph,gammacerane index,regular sterane/17α(H)-hopane,C₂₇-C₂₈-C₂₉ regular sterane,rearranged sterane/regular sterane,dibenzothiophene and fluorene,the source rocks in the northeast Sichuan Basin were marine carbonate ones with little clay deposited in anoxygenous and unhypersaline environment.The biogenic sources were plankton.