Abstract: A ball ornament with a rotary structure including a rubber fitting ring, a coupling seat, a positioning seat, a revolving disk, a transparent ball shell, and a base. The fitting ring is centrally provided with a receiving hole, and the coupling seat is received in the receiving hole of the fitting ring in tight fit and is provided with positioning posts and a central stepped coupling hole for receiving a silicon packing ring. The positioning seat is located below the rubber fitting ring and insertably connected to the positioning posts of the coupling seat. It positions a motor. The revolving disk is mounted on the coupling seat and linked-up with an output shaft of the motor by a connecting sleeve. The ball shell is provided with a curved positioning flange at a bottom end for engaging the positioning flange of the fitting ring and placed on the base. It is filled with a liquid in advance. Assembly of the ball ornament is simple and quick, and rotation thereof is smooth without problem of leakage.