A capacitive touch system and a sensing method thereof are disclosed. The capacitive touch system includes a touch panel; a touch control chip; and an active pen which includes a receiving part, a transmitting part, a control unit, and a pressure sensing element. The control unit controls the transmitting unit to output a pen driving signal according to a pen sensing signal. The pressure sensing element detects a pen pressure signal. The control unit outputs a voltage signal in responsive to the pen pressure signal after a time delay period. In the capacitive touch system and the sensing method thereof, the active pan is not required to be paired with the touch panel.