Inner diameter measurement technology with high precision and wide measuring ranges is a difficult area to master. It is challenging to achieve high precision and a wide measuring range for inner diameter measurement. The dispersive confocal technique is used to describe a high accuracy, large range approach for measuring inner diameter. The inner diameter is measured utilizing a rotating scanning approach that combines the dispersive confocal technique with least squares. Meanwhile, a plane mirror deflects the optical path of a dispersive confocal sensor, focusing monochromatic light of a certain wavelength on the object’s surface in the radial direction. The measuring range of the device may be modified to fit different objects by modifying the distance between the dispersive confocal sensor and the plane mirror, as well as the eccentricity of the dispersive confocal sensor. Furthermore, this study examines the method’s accuracy and suggests a calibration technique. As a consequence, the procedure may ensure measurement precision as well as a measurement range. Finally, experiments are utilized to test the validity of the strategy. To accomplish a 3 μm inner diameter measurement precision and a measuring range of 76 mm to 150 mm, a dispersive confocal sensor with a range of just 20 mm was utilized.