1. An image device with image defocus function, comprising: an image capture unit capturing an image corresponding to an object; a depth map generation unit generating a depth map corresponding to the object; a processor coupled to the image capture unit and the depth map generation unit for determining an integration block corresponding to each pixel image of the image according to a depth of the depth map corresponding to the each pixel image and a predetermined depth corresponding to the each pixel image, utilizing the integration block to generate a defocus color pixel value corresponding to the each pixel image, and outputting a defocus image corresponding to the image according to defocus color pixel values corresponding to all pixel images of the image; wherein the each pixel image of the image corresponds to a pixel of the image capture unit.