Based on the principle of total reflection of light, a measurement device that can study the relationship between magnetic field and refractive index of substances was designed. Using this device, the changes of refractive index of glycerol, NaCl solution and different concentrations of KCl solution were precisely measured by changing the strength of magnetic field and the the duration of magnetization. The experimental results showed that the greater the magnetic field strength, the greater the refractive index; the refractive index increased with the increase of magnetization time, and the greater the magnetic field, the shorter the time required for the refractive index to stabilize. The device encompasses various technologies including physical principles, device design, intelligent data analysis and other aspects of technology, reflecting the linkage of optical experiments and data acquisition experiments. It is user-friendly, displays data in real-time, and offers high measurement efficiency and accuracy, making it practically significant and valuable for reference in teaching and the development of instruments for measuring the refractive index of liquids under magnetic fields.