An unlocking method for a portable electronic device, and a portable electronic device and a touch-sensitive device employing the unlocking method are provided. The portable electronic device has a touch-sensitive display, and a user interface is displayed on the touch-sensitive display. The unlocking method includes respectively displaying at least one unlocking image on at least one unfixed point of the touch-sensitive display when the user interface is in a user interface locking state and sensing a touch signal of the touch-sensitive display. The unlocking method further includes switching the user interface to a user interface unlocking state when at least one click corresponding to the at least one unfixed point is detected on the touch-sensitive display.