TDI-CCD is a special photo sensor that is widely applied in aerospace remote sensing. Analyzing the MTF of TDI-CCD will be helpful to study and apply it. This paper aimed at the conclusion about the MTF of TDI-CCD push-sweeping imaging, doing the niuiieric simulation. The analysis corrected the conclusion in the literatures. Two concepts, Max-MTF and Mcaii-MTF, arc proposed with that the calculation of MTF in TDI-CCD push-sweeping imaging will be more nicety.