Abstract: A new method for measuring the refractive index of the liquid was proposed and a device was developed by using liquid film shading effect principle. Distilled water, anhydrous alcohol and 1.2-trimethylene glycol were chosen as samples to be measured. The refractive indices of these liquids were measured by the new experiment device. In the measurement process, the experimental graphs were analyzed by two methods. One used the reading microscope to measure and analyze the results directly, the other used the CCD to record and intelligently analyzed the CCD records by computer. Experimental errors were analyzed. Automatic real-time measurement was realized. Measurement results agree with the theoretical calculation. This device is simple, accurate, and easy to operate.