Improvement in optical and surfacemorphologywere observed after sulphur passivation of gallium antimonide surface. The effect of surface passivation of Te-doped n-GaSb by (NH4)2S treatment was investigated by using photoluminescence (PL), Atomic Force Microscope (AFM). The optimum passivation time is around 180 s. Under this condition, the relative PL spectrum intensity of passivated sample can be approximately 10 times stronger than as-grown sample. Meanwhile, the best luminescence homogeneity and suface morphology could be obtained.