In the application of the third-generation semiconductors, the power density of electronic devices increases and the size is miniaturization. A problem of high temperature becomes more prominent. Diamond is one of the optimum heat dissipation materials because of its ultra-high thermal conductivity and stable properties. In this review, the design principle and development process of different microwave plasma chemical vapor deposition equipment were introduced. Recent developments on different thermal applications of single crystal, polycrystalline and nanocrystal diamond were represented. Some challenges in the industrialization process combined with the 3rd-generation-semiconductors and the development direction of "larger, purer and faster" were summarized. In addition, the future research direction of diamond heat dissipation application was also prospected.