The monochrome irradiation response characteristic of high temperature glass packaging product and its surrounding scenery was analyzed as well as the irradiation response characteristic of CCD. The result showed that intersection point, which is critical wavelength, exists in the monochrome irradiation response characteristic curves of CCD to the glass packaging product and the surrounding; when wavelength is longer than the critical wavelength, monochrome irradiation response of high temperature glass packaging product will be greater than that of the surrounding scenery. It was put forward that the principle of discriminating high temperature glass packaging product from its surrounding scenery is the pixel gray difference in the wavelength longer the critical wavelength; the condition of discriminating high temperature glass packaging product in CCD image is the pixel gray of the high temperature glass packaging product greater than that of all the sceneries; in order to discriminating high temperature glass packaging product in CCD image, critical wavelength must locates in the photosensitive area of the CCD; the shorter the critical wavelength is the better the discriminating effectiveness.