Summary: We introduce a numerical solution algorithm based on a Petrov-Galerkin method in which the element shape functions are cubic B-splines and the weight functions quadratic B-splines . The motion of a single solitary wave and interaction of two solitary waves are studied. Accuracy and efficiency of the proposed method are discussed by computing the numerical conserved laws and \(L_{2} , L_{\infty }\) error norms. The obtained results show that the present method is a remarkably successful numerical technique for solving the modified equal width \(wave(MEW)\) equation. A linear stability analysis of the scheme shows that it is unconditionally stable.