Abstract: Raoyang sag is one of hydrocarbon-rich sags in Bohai Bay basin, its major source rock is Es3 lacustrine dark mudstone with strong heterogeneity. Analysis of32exploration wells by source rock logging evaluation technique converts the discrete measured TOC data into continuous data. According to the correlation between TOC and HI, the grading evaluation of heterogeneity of the source rock is presented, obtaining the thickness distribution models in terms of C and D/E organic facies. The bottom hole temperature and paleo?temperature scale parameters are applied to calibrate distribution of geotemperature field and maturity of source rocks in Raoyang sag. Trinity3D petroleum system is used to evaluate the hydrocarbon expulsion intensity of the source kitchen, which shows that the oil expulsion intensity ranges from 1.0×106 to 5.4×106 t/km2, while the gas expulsion intensity is 0.5×108~22.0×108 m3/km2