In this paper, a novel spinning-inflated-ballonet polishing tool for curved surface of mould is proposed. The head of the tool is a spherical spinning-inflated-ballonet whose inner air pressure can be controlled on-line and the head surface is covered with a suitable polishing cloth. The head can be rotated in high speed driven by an electromotor or high pressure airflow and its rotating speed can be adjusted. The flexibility of the head, the polishing force in radial direction and the contact area between the head surface and the curved surface of the work-piece can be controlled by adjusting the feeding deepness and ballonet pressure of the tool. The structure and the polishing mechanism of the novel polishing tool are introduced. The application of robot polishing system based on the novel polishing tool also is discussed. Finally the polishing control strategy of curved surface is researched.