Abstract: According to the drilling results, upper-middle Jurassic were developed in the Yellow Sea, two sporopollen assemblages for upper-middle Jurassic can be established, the Jurassic strata of this area is distinctive compared with the other place in China. The analysis of organic geochemical showed that the thickness of hydrocarbon source rocks in upper-middle Jurassic is tremendous in the Yellow Sea which showed a good prospect in hydrocarbon exploration.