在轨运行的空间相机受到温差或运动振动等影响导致像面离焦，成像质量下降。波前编码技术可以在保持光学系统整体参数不变的情况下扩展系统的焦深，使调制传递函数对离焦不敏感。将波前编码技术应用于空间同轴三反系统，提出在系统的出瞳面上加置掩模板，并对掩模板的面型进行优化，对原系统和应用波前编码技术的新系统的成像特性进行了分析和对比。讨论了波前编码掩模板的相位因子对系统的焦深延拓以及对像质的影响。理论及仿真结果表明：将波前编码技术应用于同轴三反系统，使系统对离焦不敏感，可以很好地扩大系统的焦深，对解决空间光学系统像面离焦问题具有很高的实用价值。

Temperature difference and satellite vibration lead to in-orbit space camera defocused and deteriorated image quality. The wave front coding technology can extend the depth of focus without changing the optical system structure, which makes MTF insensitive for defocus. The wave front coding technology was applied to TMC system. Optimized to the best surface type, the phase mask plate was placed in the exit pupil. The imaging characteristics of the original system and wave front coding system were analyzed and evaluated. And the phase parameter which was related to the extended ratio of depth of focus and image quality was aslo analyzed. Theory and simulation results show that the application of wave front coding technology on TMC system can be easy to extend the depth of focus. It is concluded that the wave front coding technology has high practical value to solve the imaging defocused.