Summary: In this paper, a rational elliptic function method is given by symbolic computation expansion method and a new hypothesis. Moreover, the method is quoted to obtain the new double-periodic exact solutions of many nonlinear evolution equations uniformly. In order to apply this method, we choose the \((2+1)\)-dimensional dispersive long wave equation. The result shows that we get all the solutions that Z. Yan [Comput. Phys. Commun. 153, No. 2, 145–154 (2003; Zbl 1196.35193)] received by his method. Simultaneously, more general formal solutions are derived. When using the limit of \(m\), we obtain many solitary wave solutions and soliton solutions.