For the color instrument used in the electric monitoring system,this paper proposes a fast alarm pointer recognition algorithm based on color region recognition.The traditional pointer recognition algorithms use Hough transform, with the disadvantages of a large storage space and a long time for compution. This paper combines image color information and Hough transform creatively, by identifying the color of the region where the pointer lies, judging whether to alarm output, and determining the search range of Hough transform algorithm for the accurate identification.The required memory space and computation time is reduced by reducing the search range. The improved algorithm has efficiency significantly higher than the traditional algorithm.