对矩形孔径柱面镜面形的拟合方法进行了研究，将矩形域的扩展Zernike多项式与Chebyshev多项式分别作为面形拟合基底，对导出面形数据进行波面复原，分析赛德像差与拟合基底的对应关系对比拟合结果，Chebyshev多项式较矩形域的扩展Zernike多项式有较好的像差分离能力。

In this paper, the fitting method of cylindrical mirror with rectangular aperture is studied. The extended Zernike polynomial and Chebyshev polynomial in rectangular aperture are used as the polynomial of surface fitting respectively. The wavefront is reconstructed from the surface data. The corresponding relationship between Seidel aberration and the fitting polynomial is analyzed and compared. The Chebyshev polynomial shows the good ability of separating aberration than the extended Zernike polynomial in rectangular aperture.