A motion detection system is disclosed. The invention comprises a touch panel, a plurality of switching units, a detection unit and a control unit. The touch panel comprises a plurality of metal sensors, each of which in turn is set as a detecting sensor. Each switching unit is electrically connected to a corresponding metal sensor respectively for switching voltage. During a charge stage, the detection unit calculates the discharge time of the detecting sensor and generates a detection result signal. The control unit generates a motion signal according to the detection result signal generated by the detection unit. Based on the capacitive effect and simple hardware architecture, the invention can be employed in option or orientation control by detecting a human hand's movement on the touch panel.