An under-screen fingerprint sensing device and fingerprint sensing method are provided. The under-screen fingerprint sensing device includes a fingerprint sensor and a processor. The processor performs a first FFC on a first color original value, a second color original value, and a third color original value provided by the fingerprint sensor to determine whether a target object is a real finger. When the processor determines that the target object is an unreal finger, the processor performs a second FFC on the first color original value, the second color original value, and the third color original value to determine again whether the target object is the real finger.