System for demonstrating optics principle of refractometer

The utility model provides a system for demonstrating optics principle of a refractometer, which comprises an instrument base, a light source, a lens, a light-shading cover, a reflecting mirror and a staff, wherein the light source is a laser monochromatic light source; a transparent observation surface is arranged on the instrument base; and a sealed cavity body is formed by the light-shading cover and the instrument base in a matching manner. The position relationship among the light source, the lens, the reflecting mirror and the staff is as follows: light rays are emitted from the light source and pass through the lens, reflection rays pass through the reflecting mirror when total reflection is generated, and the light rays after reflection of the reflecting mirror are shone on the staff. By adopting the system provided by the utility model, the complicated optics principle is simulated and demonstrated in real time, so that the purpose for simplifying theoretic teaching is achieved; the whole process fro