Embodiments of the present application provide a fingerprint detection device and method and an electronic device. The fingerprint detection device is disposed under a display screen of an electronic device, and includes an optical component and an optical sensor, the optical component is configured to direct or converge a fingerprint detection signal to the optical sensor, the optical sensor is configured to detect corresponding fingerprint information according to the fingerprint detection signal, the fingerprint detection signal is a reflected light signal formed by a light signal corresponding to a predetermined pattern formed in a fingerprint detection area of the display screen being reflected by a user's finger, and the predetermined pattern includes a first pattern and a second pattern; a signal intensity of a first light signal corresponding to the first pattern is smaller than a signal intensity of a second light signal corresponding to the second pattern.