The present invention relates to a color interpolation method for Bayer filter array images. The method first inputs a 3×3 Bayer pattern block with a center pixel. Next, a color filter interpolation case is determined according to the type of the center pixel. Next, Bayer pixel averages and Bayer pixel differences in horizontal and vertical directions of the color filter interpolation case are obtained. Next, missing color components of the center pixel are interpolated in both horizontal and vertical directions. Next, color differences in the horizontal and vertical directions are obtained based on the Bayer pixel differences and averages. Next, a pixel activity of the 3×3 Bayer pixel block is determined. Finally, interpolated color components in the direction of lower color differences are selected, when the pixel activity is high.