When we calculate reserves with traditional cubature, parameters of reservoir bed we use are average values. This ignores anisotropic factors of reservoirs, so that affects accuracy of calculate. To solve thisproblem, we built geologic model, and calculated reserves with the model's network data. In this method, we can increase accuracy of calculate. In this paper, we successfully applied GRIDSTATPRO, a kind of modeling software, to build an accuracy geologic model of a real gas reservoir in carbonate rock. And we also calculated reserves, according to data of our model. Compared with the traditional cubature, our result is better, because that our model meets the case of reservoir nature better. In addition, we investigated exploitable reserves of the real gas reservoir, with several methods.