A watchband assembly and a wrist-worn device having the same are provided. The watchband assembly includes a watch buckle, a watchband, a buckle tongue, and a rotating shaft for mounting the buckle tongue to the watch buckle, wherein the watch buckle includes a watch buckle upper cover and a watch buckle lower cover, the watchband and the rotating shaft are both arranged between the watch buckle upper cover and the watch buckle lower cover, and a fastener penetrates the watchband and is fixedly connected to the watch buckle to press and fix the watchband to the watch buckle. The lower surface of the watch buckle upper cover and/or the watch buckle lower cover is in contact with a human body when worn, such that the surface in contact with the human body when worn is smooth.