It is very difficult matter that polishes the internal surface of the pipe, especially to the thin pipe with the traditional surface technology. Because a usual tool cannot into the inner surface of the thin pipe and automation do not achieved easily. This paper brings up a new method that utilize the characteristic of the magnetic force line may penetrate the non-magnetic material, may using the magnetic abrasive finishing (MAF) method complete to the inner surface of the thin pipe precise polishing. The magnetic abrasive finishing does not need special equipment to complete the complex shape internal surface polishing. Moreover, we already obtained the famous processing effect through the experiment. Meanwhile this paper analyses some factors of influences efficiency, and propose some solution method.