In order to reduce the error brought by human reading, an automatic reading system for pointer pressure gauge was designed, which was used for automatic verification of gauge. The system consisted of CMOS color camera, DOME light source and a computer. This system used DOME light source to reduce the interference of environment for the images of the gauge. Gauge images were transferred via USB data cable to a computer. Firstly, binarization was used to the images. Secondly, hough transformation was used to extract the centroid of the gauge. Thirdly, the pointer and tick marks were extracted by connected region labeling method. Finally, according to the position relationship between the pointer and the two neighbor tick marks and their values, the value of pointer indicated was computed. Through the evaluation of actual gauges, the system can figure out the value of gauges in a short time, and it greatly liberates the labor force, while it has improved the efficiency of gauge verification.