Abstract: The organic matter type,abundance of organic matter and maturity of organic matter of hydrocarbon of Shuixigou formation in Shisanjianfang area had been evaluated through the geochemical test data.A hydrocarbon expulsion mode of the study area has been established by hydrocarbon-generated potential method, and the hydrocarbon expulsion characteristics has been determined.The result show that, the northwest of the study area with the thick source rock, the thickness between 350-600m,the average is 480m.Higher abundance of organic matter and the thermal evolution stage is between maturation to high maturation, the organic matter types mainly for class Ⅱ and Ⅲ, has a certain hydrocarbongenerating potential.The expulsion threshold depth of coal petrography in the Shuixigou Ground of the study area is 2000m, and the biggest hydrocarbon expulsion rate is 530mg/g.In the 2500m, quickly reaching the peak of hydrocarbon expulsion, and the biggest hydrocarbon expulsion rate is 150mg/(g·hm).The expulsion threshold depth of coaly mudstones in the Shuixigou Ground of the study area is 2200m, and the biggest hydrocarbon expulsion rate is 320mg/g.In the 2800m, quickly reaching the peak of hydrocarbon expulsion, indicating that the study area has certain exploration potential.These research results have certain reference significance of the hydrocarbon expulsion study for the area which has the similar geological conditions.