When we measure glass thickness using the traditional triangulation method, the relative position of the glass and probe should be kept fixed. When the position of the glass changes, it must be recalibrated to accurately measure thickness. To address this problem, a multi-position glass-thickness-measurement method based on laser triangulation that can automatically adapt to displacement changes is proposed in this paper. By this method, glass thickness can be measured directly when glass position changes. Firstly, the relationship between the glass thickness and spacing of imaging spots of the reflected light from the front and back surfaces of the glass is analyzed when the glass is at the standard position. Then, the relationship among the spacing of imaging spots, position of front surface of the glass, and glass thickness is analyzed when the glass displacement changes. The corresponding mathematical model is established, and a compensation algorithm is proposed herein to correct the influence of the glass displacement change on the glass-thickness measurement. Finally, a laser triangulation system based on a laser-diode-complementary metal-oxide semiconductor (LD-CMOS) is designed, and multiple glass samples with known thicknesses are used for calibration and measurement experiments. Experimental results show that when the glass position changes within the range of 1-4.5 mm, the absolute errors of glass-thickness measurement at different positions are less than 0.010 mm and the relative errors are within 0.5%. The proposed method can thus realize high-precision glass-thickness-measurement without repeated calibration when the glass is at different positions, displaying good practicability, flexibility, and versatility.