Abstract: During the process of the development of gas condensate reservoir, the gas-liquid two phases have formed due to the appearance of condensate oil along with the decrease of formation pressure. Because of the existence of adsorption and capillary pressure, there is a large difference in material balance equation between the traditional gas reservoir and gas condensate reservoir. This paper sets up the material balance equation of gas condensate reservoir, which considers the affection of adsorption and capillary pressure, to calculate the reserves and predict yield of gas condensate reservoir. The result shows that the reserves and predicted yield calculated by the method are smaller than that are calculated by traditional material balance method and material balance method without considering the impact of adsorption and capillary pressure, and it is more matching with the actuality. With the increase of the condensate content, the difference between three methods of calculation will increase. It is instructive to the development of gas condensate reservoir.