A Bluetooth earphone and an ear-hook device thereof are provided. The Bluetooth earphone includes an earphone body and an ear-hook device. The ear-hook device includes a hinge assembly and an ear hook. The hinge assembly is rotatably disposed on the earphone body. The ear hook is rotatably disposed on the hinge assembly. As a result, the ear hook is able to rotate around the earphone body on two different axes via the hinge assembly, such that a user can selectively wear the Bluetooth earphone on his or her left ear or right ear.