Analysis the characteristics of meter digital structure, considering the complexity of the meter digital images background, combines dynamic threshold and global threshold binary image on instrument digital image pre-processing. Locating the digital on the instrument, eliminated pattern noise by opening operation and removed small adhesions between the digital and the border, utilized the connected domain screening method to fulfill the meter digital precision positioning. Discussed recognition methods of meter digital based on eigenvector. The results showed that the recognition rate of this solution was 97.5%, and the recognition speed was extremely fast, which perfectly met the recognition requirements: accuracy and speed.