A fingerprint sensor includes a substrate, a sensing electrode over the substrate, a first electrode and a second electrode. The sensing electrode is configured to detect a capacitance in response to a touch event on the fingerprint sensor. The first electrode is disposed between the substrate and the sensing electrode, while the second electrode is disposed between the first electrode and the sensing electrode. The first electrode and the second electrode are configured to define a capacitance therebetween. The sensitivity of the fingerprint sensor is inversely proportional to the capacitance between the first electrode and the second electrode.