相位板的加工精度直接影响着相位型星冕仪成像系统的性能。推导了六平台相位板的误差公式，并分析了相位板结构的微小变化对六平台相位板星冕仪的消光性能和消色差性能的影响。数值模拟结果表明，对特定波长的单色光，相位板相位水平高度的误差和倾斜角的误差都会降低六平台相位板星冕仪的消光性能。但是相比较而言，消光能力对相位阶跃处的倾斜角的误差更为敏感。在宽带范围内，考虑消色差性能，相位水平高度误差只会使其中心波长发生偏移；而相位阶跃处倾斜角的微小误差则会极大地降低其消色差性能。

The machining precisions of phase mask directly affect the performance of a stellar coronagraph imaging system. The error formula of six-level phase mask is derived. The influences on the extinction and the achromatic performance are analyzed when small errors of phase mask are induced. The numerical simulation results show that the errors of phase horizontal hight of phase mask and tilt angle variation can reduce the extinction performance for the monochromic light of specific wavelength. However, in comparison, the coronagraph extinction performance is more sensitive to the tilt angle errors. With in the scope of the broadband, considering the achromatism ability, the level height error can only affect its central wavelength, whilethe small errors of tilt angle can greatly degrade its achromatic performance.