A fingerprint sensing module includes a fingerprint sensing pixel array, a plurality of column circuitries and a constant current circuit. The fingerprint sensing pixel array includes a plurality of sensing pixels in an array arrangement. Each column circuitry is electrically coupled to a row of the sensing pixels via a corresponding row signal line. The constant current circuit generates a bias voltage to the column circuitries according to a reference current. In response to the bias voltage level, a row output current provided by each column circuitry and flowing through each row of the sensing pixels is equal to or close to the reference current. Since the row output current coincides with the reference current, the row output current is not adversely affected by the external factors.