An electronic apparatus and an under-screen fingerprint sensing method thereof are provided. The electronic apparatus includes a processing circuit, a touch panel, and a fingerprint sensing apparatus. The processing circuit is coupled to the touch panel and the fingerprint sensing apparatus. The fingerprint sensing apparatus includes a plurality of optical fingerprint sensing units. The touch panel provides touch information of a finger to the processing circuit in response to the finger touch detected by the touch panel. The processing circuit determines a fingerprint sensing region based on the touch information and drives a plurality of first sensing-enabled-units among the optical fingerprint sensing units based on the fingerprint sensing region, such that the fingerprint sensing apparatus obtains a fingerprint image of the finger via the first sensing-enabled-units. The first sensing-enabled-units are a part of the optical fingerprint sensing units.