Abstract: The North Yellow Sea Basin,a Meso-Cenozoic basin,which is located in northern Yellow Sea,is in the earlier stage of evaluation according to its low degree of exploration.This paper analyzed the richness,type and maturity of the organic matter of the well drilling source rocks in eastern of the basin.The results indicate that Upper Jurassic source rock is the chief one which is supposed to be most potential,in addition it is the effective source rock of crude oil discovered at present.And Lower Cretaceous source rock is the best one in this area,but its maturity is lower,so it must be taken consideration into as potential oil source rocks.This research is an important complement and enhancement to source rock in understanding there,and gives well instruction to hydrocarbon exploration as well.