Abstract: The structure and parameters of the nozzle of a jetmill device are optimized, numerical simulations of the inner structure are carriedout with hydrokineticssoftware, the stress analysis of the structure is conducted with finiteelement software, and the effects of inlet diameter, section area of throat region, passageshape and diffusion angle on supersonic nozzle are analyzed. Optimizedoperation parametersinclude pressure of 3.5\,MPa and inlet diameter of 6\,mm after comparingdifferent simulations. In the range of 8^\circ \sim 12^\circ, the diffusion angle has little effect on the performance of the designed supersonic nozzle.