The modified Michelson interferometer is used to measure the refractive index of sucrose solution. The device uses the OpenM camera to identify the interference fringes ,the gear motor and the stepper motorto measure the displacement ,and the Arduino microcontroller to control and calculate.The modified Michelsoninterferometer effectively alleviates the visual fatigue in the operation process and reduces the error. Therefractive index measured by experiments accurate and consistent with the theoretical results. Therefore , thedevice can be widely used in college physics experiments, and also provides potential for further industrialapplications.