An automatic focusing structure includes a holder (20), a barrel (10) and a piezoelectric actuator (30). The holder has a resistor (26) thereon. The barrel is slidably received in the holder. At least one lens element (12) received in the barrel, and an electrode (16) is located on an outer periphery wall of the barrel. The electrode slidably contacts the resistor. The actuator mounted under the barrel to move relative to the holder. When the barrel slides relative to the holder, the resistance value of the resistor is changed. Information from the resistor corresponds to a position information of the barrel, and the position information is feedback to the actuator so as to adjust the position of the barrel.