A method of improving the accuracy of traditional methods (Guru and Chen [6], Hagmann and Gandhi [7]—[8], Hagmann and Levin [9], and Livesay and Chen [13] of solving integral equations has been obtained. We now have exact formulas for the accuracy of protective approximation methods (Gohberg and Feldman [5], Neittaanmaki and Saranen [20]) for solving integral equations. For a class of approximation schemes for estimating the solution of integral equations of electromagnetic scattering, we can develop a systematic procedure for reducing the original infinite rank integral equation to an exact finite rank integral equation capable of being completely analyzed by digital computer. In this paper the method is illustrated for the popular pulse basis function method(Guru and Chen [6], Hagmann and Gandhi [7]—[8], Hagmann and Levin [9], and Livesay and Chen [13]).