The echelle spectrometer is a major spectroscopic instrument with its high spectral resolution in a wide range of applications. The spectral reduction technique is the core of the data processing of the echelle spectrometer, which realizes the rapid reduction of two-dimensional images to one-dimensional spectra by establishing the correspondence between wavelength and imaging position. The performance of the echelle spectrometer is directly determined by the accuracy of spectral reduction, which is the most important point and greatest difficulty in instrument development. In view of this, the development of the spectral reduction technique is reviewed, and its evolution is classified into three stages: ray tracing, modeling, and calibration methods. The core ideas and principles of spectral reduction algorithms in each stage are discussed in detail. Finally, the development history is summarized, the development trend is predicted, and the outlook of the development direction for the echelle spectrometer spectral reduction technology is discussed.