The present invention provides a security functional thin film and a security product containing such a thin film. The security functional thin film is of an amorphous structure, and possesses soft magnetic characteristics. Large Barkhausen effect can be detected along the in-plane preferred direction of magnetization; and the Large Barkhausen effect significantly attenuates, or no such signal can be detected, in a direction perpendicular to the in-plane preferred direction of magnetization. The thin film has a thickness of 20-300 nm, and the thin film also possesses element encoding characteristics that can be authenticated by experts. The security functional thin film of the present invention can be fabricated by magnetron sputtering web coating process. The security product provided by the present invention has a security information layer formed of the security functional thin film, and can be combined with other security characteristics for use in fabricating security materials such as security threads, security tapes, paper security strip-like inserts, or security labels, and others. Compared with conventional anti-counterfeiting technologies, the instant security functional thin film has more hidden security information, and facilitates enhancement of safety performance of security products.