Diamonds with excellent thermal conductivity have proven to be effective in addressing heat dissipation challenges. However, with the increasing power of electronic devices, the demand for surface heat dissipation capability is growing higher. Continuously improving the thermal performance of diamond devices is conducive to promoting the development of high-power electronic components. In this study, a novel diamond coating with microgroove-submicron cone composite structures was prepared by inductively coupled plasma etching technology, microwave plasma chemical vapor deposition and bias plasma etching technology. Droplet evaporation experiments demonstrated that the evaporation time of droplets on diamond coatings with microstructures and diamond submicron cones was 42 % shorter compared to ordinary diamond coatings. This finding indicates that surface micro-submicron structures play a crucial role in enhancing the solid-liquid heat transfer performance of diamond heat dissipation devices. The micro-submicron structures create a significantly larger contact area, which leads to enhanced heat transfer, active bubble generation, and droplet vibration phenomena, thereby facilitating bubble escape. Furthermore, the surface generated by ion etching exhibits graphite phase and terminal oxidation, which enhances the hydrophilicity of the surface phase and further improves the heat transfer efficiency of solid-liquid.