Benefited from the excellent physical and chemical properties of diamond, chemical vapour deposition (CVD) diamond thin films have attracted continuous attentions among researchers regarding to both basic research and industry application like cutting tools, biomedicine, thin film sensors and micro-electromechanical systems etc. In this paper, recent progress in the field of diamond film research is reviewed. It is mainly focused on various synthesis methods of diamond thin films and comparison of their pros and cons. By introducing the growing mechanism of CVD diamond thin films, strategies to improve the deposition rates and quality of diamond thin films are also discussed.