Abstract: Worldwide patent documents about diamond thin films from 1975 to 2008 were collected in this paper. Associated patent databases were established. The development thread and competition pattern of this technology were investigated on both of technology and competitiveness upon quantitative, qualitative and cited analysis. Results show that: (1)Diamond films cutting tools technology in worldwide has been at a more mature stage;(2)The United States and Japan not only pay attention to basic research and applied basic research of this technology but also emphasize original technology development and the protection of intellectual property; China attaches great importance to papers published and neglect patents applications;(3)The vast majority of this technology patents of United States and Japan were developed by enterprises, while China by universities.The patent strategy of this technology about further research and development in China were discussed.