A redeye image detection method for detecting at least one redeye image in an input image includes: deriving an edge detection result by performing an edge detection process to detect an edge characteristic of the input image; deriving a red pixel detection result by performing a red pixel detection process to detect red pixels in the input image, and utilizing a determining circuit to derive a preliminary detection result according to the edge detection result and the red pixel detection result, and derive the redeye image according to the preliminary detection result.