Influences the alignment errors on the image quality of the large segmented mirror are theoretically analyzed and numerically simulated formed by seven hexagonal segments in the thesis.By employing the properties of the Fourier-transform,an analytic Fourier-transform method is presented that can be used to deduce the point-spread-functions of the segmented mirror with alignment errors.Based on the Fast-Fourier-transform technique,the point-spread-functions in the presence of edge misconfigure,transverse excursion,and tilt errors on an individual segment are simulated.And the image qualities are numerically simulated according to the imaging principle.It is revealed that the edge misconfigure errors almost have no influence on the image qualities,but the influences due to the transverse excursion errors are relatively intensive in comparison with that due to the tilt errors.