A mask inspection device and method thereof are provided. In the mask inspection device, an image capturing module is controlled to capture an image of the object to be inspected, and when the captured image does not match a predetermined correction image, a horizontal position of the bearing module which holds the object is adjusted; when the captured image matches the predetermined correction image, a light emission element projects a spot light towards the object, and the image capturing module captures an image in a mask region of the object, so as to produce a mask inspection image. The mask inspection information can be obtained from a two-dimensional image of the mask inspection image, and an abnormal image of the mask inspection image is inspected to generate mask abnormal information.