In this paper, we introduce a new technique in semi-analytic method for solving non-linear differential equations. At first, a non-linear differential equation will be converted to a linear differential equation (or some of them) by using homotopy method. Then, for finding parameter a in the linear differential equation we use Galerkin method, which is easier and less computations in comparison with similar methods, such as [5, 7]. Then, we will solve linear differential equation by using analytic method where it's evident that analytic method is better than the vibrational iteration method in [1, 3]. Also in [7] perturbation techniques are depend on small parameter but the above mentioned method is not depend on small parameter. The obtained results are shown the high accuracy.