Abstract: To analyze the neutronics characteristics in the fuel design of micro gas-cooled reactor, the influence of main parameters of TRISO particle and fuel pellet on the neutronics characteristics of the square fuel assembly model was investigated using Monte Carlo program RMC. The results show that the lifetime increases with the kernel diameter smartly at the beginning and then becomes smooth gradually when the TRISO particle packing fraction and coating layer thicknesses are invariable, and decreases with the increase of the coating thickness when the volume fraction of fuel particles and the diameter of fuel core are invariable. The lifetime is influenced by the coating layer thicknesses slightly, and will be longer as the fuel pellet diameter bigger when the uranium loading is invariable. While the no-fuel zone thickness has a remarkable negative impact on the neutronics characteristics, and the matrix density and the matrix impurity boron equivalents have a weaker impact. These results will instruct the follow-up design and optimization of coated particle dispersion fuel for the micro gas-cooled reactor in the future.