Recently, Dehghan et al. presented the diagonal and off-diagonal splitting (DOS) iteration method for solving the linear systems Ax = b [3]. In this paper, we improve its convergence rate with extrapolation. Also convergence analysis of extrapolated DOS (EDOS) iterative method is studied by giving an upper bound of the extrapolation parameter, then consistency of EDOS and its optimal extrapolation parameter are discussed. Finally, several numerical examples are given to show the efficiency of the presented method.