To detect the salient regions in images quickly and efficiently, using information of difference between color channels and spatial information, this paper proposes a saliency detection approach based on comparison of color channels. The algorithm regarded the saliency detection task as a process of separating and identifying the foreground region and the background region of the image. Firstly, it defines a set of color channels based with RGB color space, and separates regions with different colors in image by making comparisons between different channels. Then, it selects foreground regions by analyzing spatial information. Lastly, it combines all foreground regions to obtain the final saliency map. We evaluate and compare the performances of our algorithm against previous algorithms on two public datasets. The experimental results show that our algorithm has lower computational complexity and high precision and recall rate, and prove that our algorithm is simple and effective.