The properties of the spin-valve structure, based on two ferromagnetic layers divided by a layer of non-magnetic metal, in the geometry of the current perpendicular to the plane are modeled. In addition to well-known classical twochannel conductivity model proposed by Nevill Mott, the developed model takes into account spin scattering on the surface between structures. The developed model uses equivalent electrical circuits to simulate a spin valve with parallel and antiparallel alignment. On the basis of this model, the dependences of the giant magnetic resistance on two geometric parameters of the structure—the ratio between the thickness of the free and the thickness of the fixed layers, and their ratio to the length of spin diffusion—are derived. Based on the developed model, numerical data are obtained for the spin valve, where the ferromagnetic layers are made of cobalt, permalloy, iron, and nickel. The portion of surface scattering in the giant magnetic resistance is also investigated. A general conclusion is made about the slight increase of the giant magnetic resistance due to the influence of surface scattering for structures based on cobalt, permalloy, and iron, but not for nickel. This outlines the scope of applicability of the developed model.