The refractive indices of LGS in visible light region were measured without impairment by the reflection ellipsometry method. The refractive dispersion curve of LGS was fitted to Sellmeier's equation. 采用反射式椭圆偏振光谱技术,在可见光区无损伤的测量了小尺寸LGS晶体样品的折射率,拟合了Sellmeier色散方程。