The processing of shale cap rock preventing hydrocarbon breakthrough in lithological reservoir is a course of impetus subdue resistance. On the basis of theory，the article establish the hydrocarbon sealing dynamic model and mathematic model for shale cap rock of lithological reservoir. The models indicate that hydrocarbon breaking shale cap rock in lithological reservoir is a dynamics balance phenomenon. The impetuses include the formation pressure of reservoir and buoyant force. The resistances include the formation pressure of shale cap rock and capillary pressure. Following the restoration of the paleoporosity and paleoburial depth，the impetus and resistance of hydrocarbon breaking shale cap rock in oil pool forming period can be contrasted，and the cap formation sealing capability evolution can be quantitatively study. From the application of the models，we can found that the Sangonghe group and Xishanyao group of Jurassic System lack effective mudstone cap rock in the end of Jurassic. The effective mudstone cap rock is existing in lowermiddle part of Sangonghe group and the sealing ability of Xishanyao group is very generalized in the end of Cretaceous.