In order to measure thickness of optical elements with low cost and high precision in optical factories, astigmatism thickness measurement technology was used to build the measurement system. Theoretical analysis and experimental verification were carried out. In this system, astigmatism was introduced into cylindrical mirror to form elliptical spot with thickness-dependent aspect ratio. The thickness of components was obtained based on real-time image processing with high measuring efficiency. Finally, measurement experiments were carried out with commercial glass plates and concave lenses. The results show that measurement uncertainty of the system is less than 2μm when confidence probability is 95%. Measuring range of center thickness is 25mm and it can meet current general processing tolerance requirements. The device has the advantages of simple operation, high accuracy and low cost. It can be used to measure transparent and opaque materials with a wide range of application. The device provides a low-cost, non-contact and high-precision thickness measurement scheme for enterprises and is suitable for small and medium-sized optical processing enterprises. It has broad application prospects.