The triple differential cross section for Ar（3p6） in the special geometry of coplanar large energy loss and close to minimum momentum transfer has been calculated with the modified distorted wave Born approximation （DWBA）. The polarization interaction between the electron and the target, especially in the near-target region, and the post-collision interactions are included in the calculation. The theoretical results with modified DWBA are compared with the recent experimental data, the standard DWBA and DWBA-G. It is shown that the polarization are very important in the calculation of TDCS in coplanar asymmetric （e,2e） reaction.