Offner成像光谱仪在大色散需求下成像质量不足并且易发生光线遮挡，为此设计了一种基于罗兰圆条件的非共面Offner结构光谱仪。分析并推导出了一种非共面Offner结构成像光谱仪的消除像散及彗差同时解决光线遮挡的设计方法。使用该方法设计出光谱范围为350~1000 nm，色散宽度为12.6 mm 的成像光谱仪。在奈奎斯特频率(30 lp/mm)下其调制传递函数在全视场、全光谱范围优于0.78，点列图均方根半径优于4 μm，同时，系统的谱线弯曲及谱带弯曲均小于1%像元尺寸。最后，将非共面Offner结构成像光谱仪与传统Offner结构进行对比，结果表明，在高光谱分辨率需求下，当入射狭缝较小时，非共面Offner结构光谱仪具有更好的成像质量，并且在谱线弯曲及谱带弯曲的控制上具有优势，可用于小体积高光谱分辨率成像光谱仪器设计。

The image quality of the traditional Offner spectrometer may be unsatisfied when large dispersion is needed. Furthermore, severe ray obstruction may occur when relative aperture is not small enough. Therefore, an off-plane Offner spectrometer is suggested based on Rowland condition in this paper. An analytical design approach of an imaging spectrometer based on off- plane Offner configuration is presented. Astigmatism and coma are corrected in the design without ray obstruction. An imaging spectrometer is designed using the configuration with a spectral range from 350 nm to 1000 nm. The size of the spectral image is 12.6 mm. The modulation transfer functions in total fields of view and the whole spectral range are more than 0.78. The root mean square (RMS) spot radiuses are smaller than 4 μm. Meanwhile, the smile and keystone of the system are both better than 1% of a pixel size. Finally, a contrast between the off-plane Offner spectrometer and the in-plane configuration is performed. The result demonstrates that the off-plane Offner spectrometer has a better image quality for high spectral resolution if a shot entrance slit is allowed. There is also an advantage in eliminating the smile and keystone. The configuration can be applied to imaging spectrometers with small dimension and high spectral resolution.