A method for collecting information in image-error compensation is provided. The method includes providing a reticle having a first image structure and a second image structure; moving a light shading member to control a first exposure field; projecting a light over the first exposure field; recording an image of the first image structure after the light is projected; moving the light shading member to control a second exposure field; projecting the light over the second exposure field; and recording an image of the second image structure after the light is projected.