Touch device and control method and method for determining unlocking thereof

A touch device and a control method and a method for determining unlocking thereof are provided. The touch device includes image capturing units configured nearby a touch surface respectively, and light-reflected object are configured around the touch surface. In this method, a first gesture on the touch surface is received by detecting a reflected signal by image capturing units when the touch device operates in a touch-lock mode. The image capturing units emit a detecting signal and detect the reflected signal reflected from the detecting signal. Then, whether the first gesture matches a first specific gesture is determined. When the first gesture matches the first specific gesture, the touch device is executed in a touch-on mode. A touch signal is provided when the touch device is executed in the touch-on mode but not provided when the touch device is executed in the touch-lock mode.