Ion beam epitaxy (IBE) technology is a significant method for preparing high pure and high quality rare-earth functional films at low growth temperatue. A new method of preparing rare-earth functional films by ion beam epitaxy was reviewed in details. The recent developments and application of IBE on rare-earth functional films is focused, particularly for high-K materials CeO_2, photoluminescence materials Gd_2O_3 and magnetic semiconductor materials Si_ 1-xGd_x. Ion beam epitaxy (IBE) technology is a significant method for preparing high pure and high quality rare-earth functional films at low growth temperatue. A new method of preparing rare-earth functional films by ion beam epitaxy was reviewed in. The recent developments and application of IBE on rare-earth functional films are focused, particularly for high-K materials CeO 2, photoluminescence materials Gd 2 O 3 and magnetic semiconductor materials Si 1-xGd_x.