中阶梯光栅光谱仪通过交叉色散形成的二维光谱图,无法直接对入射光的波长进行光谱标定。为此，建立了C-T型棱镜透射式中阶梯光栅光谱仪的谱图还原模型，分别分析了棱镜和光栅色散方向的色散规律以及棱镜与光栅之间的相互作用关系，并且建立了波长与像面坐标的关系表达式。根据该类中阶梯光栅光谱仪的光路结构特点，以及光束在各个光学元件的传输特性，校正各光学元件引入的坐标计算误差，最终精确计算出波长所对应的像面坐标,完成谱图还原模型的建立。通过该方法建立的模型可快速准确地对该类型中阶梯光栅光谱仪二维谱图进行谱图还原及波长标定，模型的计算误差小于一个像元。

As the cross dispersion, the two-dimensional spectrum of echelle spectrometer cannot calibrate the wavelength spectrum directly, therefore the spectrum reduction model for the transmission prism echelle spectrometer with the C-T structure is built. The dispersion rule and relationship between prism and echelle is analyzed, and the relational expression of wavelength and image coordinates is also established. According to the optical structure and optical transmission characteristics, the deviation of coordinates caused by the element can be regulated, and the accurate image coordinates can be calculated. Finally the spectrum reduction model is accomplished. This model can recover the two-dimensional spectrum of echelle spectrometer quickly and accurately, and calibrate the wavelength. The error of image coordinates calculated by the model is less than one pixel.Key words