Development of superhard materials is divided into six stages or classified into five kinds of products (exploring stage; synthetic diamond and cBN by highpressure and high temperature (HPHT) technology; single crystal cutting tools; synthetic diamond by Chemical Vapor Deposition (CVD) technology; new superhard materials) according to the extending of application fields, and detailedly overviewed along to the main line of synthetic diamond and related materials and tools. The advantages and potential capacity of superhard materials seen as next generation materials for cutting tools are discussed from three aspects of their own performances, development of high performance machined materials, and improving machining efficiency and saving cost. Some potential limitations and possible solutions for superhard cutting tools in preparations and applications are also proposed.