The symplectic algorithm is the algorithm that preserves the Wronskian determinant and the symplectic scheme is applied to the calculation of the l-dimensional model of strong field. The numerical results indicate that the Wronskian determinant calculated by using the symplectic algorithm keeps unchanged which is in good agreement with theoretical analyses, but the Wronskian determinant calculated by using the Runge-Kutt algorithm increases rapidly after a long distance of computation.