An electronic device includes a storage unit, a touch-sensing unit and a processing unit. The storage unit stores a plurality of combinations of at least two shapes. The touch-sensing unit detects the touch of a first touching object and a second touching object while the electronic device is in an idle mode. The touch-sensing unit further generates a sensing signal when the capacitance values corresponding to the first touching object and the second touching object are within a predetermined range over a predetermined time, and the combination of the shapes of the first touching object and the second touching object conforms to one of the combinations stored in the storage unit. The processing unit enables an application program according to the sensing signal.