The present invention discloses a document scanning method, a document scanning device and a portable electronic device. The document scanning method comprises capturing a plurality of images of a plurality of blocks of a document by an image capturing device; adjusting characteristics of the plurality of images according to distances between the image capturing device and the plurality of blocks when the image capturing device is capturing the plurality of images, to generate a plurality of adjusted images; determining a plurality of characteristic points of each of the plurality of adjusted images and a plurality of characteristic vectors corresponding to the plurality of characteristic points; and combining the plurality of adjusted images according to the plurality of characteristic vectors corresponding to the plurality of characteristic points of each of the plurality of adjusted images, to generate a scanning result of the document.