An algorithm based on Sumudu transform is developed. The algorithm can be implemented in computer algebra systems like Maple. It can be used to solve differential equations of the following form automatically without human interaction \begin{displaymath} \sum_{i=0}^{m} p_i(x)y^{(i)}(x) = \sum_{j=0}^{k}q_j(x)h_j(x) \end{displaymath} where pi(x)(i=0, 1, 2, ..., m) and qj(x)(j=0, 1, 2, ..., k) are polynomials. hj(x) are non-rational functions, but their Sumudu transforms are rational. m, k are nonnegative integers.