An image capturing method of a touch display module is disclosed. The image capturing method includes the steps of defining a first axial; defining a second axial which is perpendicular to the first axial; detecting a motion track on the touch display module, wherein the motion track includes at least an angle or a curve; calculating a first length which is the length of the motion track projecting to the first axial; calculating a second length which is the length of the motion track projecting to the second axial; and capturing a selecting range according to the first length and the second length. This invention also discloses an electronic device.