Abstract: Accurate acquisition of the physical quantities to be measured is a prerequisite for achieving precise measurements. Currently, high-precision and expensive CNC gear measuring instruments are widely used. However, for micro gears with a modulus less than 0.1 mm and a diameter less than 1 mm, traditional contact measurement methods cannot measure the complete tooth profile due to the narrow tooth groove width. Optical measurement methods also face the problem of not being able to obtain tooth root data due to tooth occlusion and tooth surface inclination limitations. In response to this situation, a high-precision measurement method for micro gears based on white light interferometry is proposed. Real-time monitoring of the micro gear end face tilt is achieved based on the appearance order of interference patterns, ensuring the extraction accuracy of the gear profile. The gear center is determined based on the three-dimensional point cloud data of the end face, effectively improving the gear centering accuracy. The white light interferometry measurement principle for micro gears, the end face leveling model, and the gear error calculation method are introduced in detail. Experimental results show that this method can achieve high-precision measurement of micro gears, providing an effective means to solve the precision measurement problem of micro gears.