To meet the demand of wide-swath and long-wave infrared hyperspectral imaging, a new design method of low-cost, light and miniature hyperspectral scanning imaging system for ground imaging is proposed on the basis of photoconductive HgCdTe linear detectors and plane blazed rasters. The system has 150 continuous spectral segments and a 30° imaging field angle in the 8~12.5 μm long-wave infrared range. It consists of a raster scanning mechanism and a field-of-view scanning mechanism, both of which are controlled synchronously to achieve fine light splitting and wide-swath imaging. The relations both between the angle of raster scanning and the detector received monochromatic wavelength and between the field-of-view scanning angle and the imaging field angle are deduced. On the basis of analyzing scanning positioning accuracy, a scanning system which uses a stepper motor as the core of motion and uses an operating mode of `whisk positioning+stop imaging'' is designed. The experimental result shows that the scanning system can meet the requirements of field of view positioning accuracy and light splitting accuracy. In addition, the silicon carbon emission spectrum curve obtained in the long wave infrared range shows that the design of the system is reasonable and effective. The design method of this scanning system is of guiding significance to the design of long-wave infrared hyperspectral systems.