Many problems which arise in mathematical physics, engineering, biology, economics,...etc., lead to mathematical models described by nonlinear integral equations. The aim of this research is to find the solution of nonlinear Volterra and Fredholm integral equation by using analytical and numerical methods such as the degenerate kernel method, the successive approximation method, the projection method, and the Nyström method. Also, we applied the new combination of Newton-Kantorovich method with modified Simpson method. Most of them transform the nonlinear integral equation into a system of linear or nonlinear algebraic equations. Finally, numerical examples are presented which demonstrate the robustness of the expansion numerical methods in determining solutions.