The invention discloses a learning device based on a digital book. The learning device can provide functions of learning and understanding knowledge points in content of the digital book in addition to reading the digital book normally. The learning device is characterized in that: a knowledge point structure is preset on the digital book, and the knowledge points in the knowledge point structure come from the content of the book. Generally, an author teases out the content in the digital book, decomposes a plurality of knowledge points from the content, and carries out structured processing on the knowledge points, so as to form the knowledge point structure. The knowledge point structure completed by the author is enclosed in the digital book, and the user can refer to the knowledge point structure while reading image-text content of the book. In addition, the learning device further provides a function of reconstructing the knowledge point structure of the book by the user, thus the user can reconstruct the knowledge point structure based on own understanding, and upload the reconstructed knowledge point structure to the server to share with other users.