Abstract: After heat-treated the as-prepared 47.5GeS₂-17.5Ga₂S₃-35AgCl glass at 275℃（T_g-40℃） for 6~48h,chalcohalide glass ceramics that have optical second-order nonlinearities were prepared successfully.According to the results of X-ray diffraction（XRD）,optical transmission spectrum and scanning electron microscope（SEM）,it can be shown that AgGaGeS₄ crystallites which have an average size of hundreds nm separated out and dispersed in the whole bulk glass ceramics.The second harmonic generation（SHG） effects of the glass ceramics were studied by Maker-fringe technique.The origin of the observed SHG was mainly ascribed to the separated out AgGaGeS₄ nonlinear optical crystallites.The Maker-fringe patterns observed were broad lobe enveloping,whereas have no interfere fringes.The maximum SH intensities appeared at incidence angle of 0°,and were comparatively one third of α-SiO₂ single crystal.They are promising to be applied in the electro-optic modulators of infrared spectral region.