The invention provides an electronic device and a user interface display method. The electronic device comprises a display unit, a touch unit, a processing unit and a storage unit. The display unit is used for displaying an electronic notebook in a set display area, and the electronic notebook comprises an edit region; the touch unit is used for receiving a touch signal; the processing unit is used for widening the edit region from an original size to a first size by a proportion according to the touch signal, narrowing the edit region from the first size to the original size by the same proportion according to a storage signal, and reducing resolution of notebook content in the edit region from a first resolution corresponding to the first size to a second resolution corresponding to the original size; the storage unit is used for storing the electronic notebook according to the storage signal. The display unit displays the notebook content corresponding to the original size after the storage unit stores the electronic notebook. The electronic device and the user interface display method have the advantages that troubles in change of lines or pages can be avoided to improve reading convenience.