The present invention discloses an image pickup device, an image preview system and an image preview method thereof. The image pickup device comprises an image pickup module, an image processing module and a display module. The image pickup module is arranged for capturing a plurality of images. The image processing module is arranged for scaling down pixels of each image to generate a plurality of adjusted images, and combining the plurality of adjusted images to generate a preview image. The display module is arranged for displaying the preview image. Wherein, the image processing module is arranged for rendering a high dynamic range image according to the plurality of images while the plurality of adjusted images is blended.