Contrast enhancement has an important role in image processing applications. Conventional contrast enhancement techniques either often fail to produce satisfactory results for a broad variety of low-contrast images, cannot be automatically applied to different images. Because their parameters must be specified manually to produce a satisfactory result for a given image. So, this paper proposes a new contrast enhancement method based on the K-means algorithm. This method is to cluster the histogram components of a low-contrast image using K-means algorithm. And then these clustering histogram components are stretching and equalizing. From the experimental results, the proposed method was more effective than conventional contrast enhancement techniques.