Abstract: There are close relationship between the dynamic changes of seepage field in reservoir slope and reservoir water level. The traditional analysis methodology based on saturated seepage law can not describe the dynamic change law of seepage in slope while reservoir water level rises. From the theory of unsaturated and transient seepage and on the basis of getting the relationship between matric suction and volumetric water content in laboratory experiments, through experimental data fitting, Van Genuchten model parameters of the soil hydraulic characteristics have been got. Taking a typical slope in Three Gorges Reservoir area as an example and simulating uniform water level rise in reservoir, the slope showed seepage characteristics in four soil media, that is silty clay, silty soil, sand or gravel soil, and the pore water pressure change at the elevation of 165 meters and 155 meters of the slope has been monitored. The result shows that the seepage line showed a "V" shape in the slope with the uniform water level rise, and at each time step the connection line of the turning point has gradually the trend to be parallel with the slope with increased permeability. The variation regularities of pore water pressure with time in four types of soil have been revealed. The research results can provide important reference for the control of reservoir bank.