Abstract: Microencapsulated fuel is the fuel pellet or fuel rod which formed by coated fuel particles dispersed in the matrix, and it is one of the most potential accident tolerant fuel(ATF) fuel. Coated fuel particles can be tristructural isotropic(TRISO) or bistructura isotropic(BISO), and the matrix is metal or ceramics. Based on the ABAQUS software, the metal matrix microencapsulated fuel is calculated. By analyzing the effect of the coating thickness on the fuel performance, suggestions for the optimization are given. The results showed that the thicker the Buffer is, the higher the burnup for the failure is, and thus, the increasing of the Buffer thickness should be considered in the design. The thicker the IPyC layer is, the larger the maximum hoop stress is, and thus, its thickness should be reduced in the design. The thicker the SiC layer is, the smaller the hoop stress is, and thus, its thickness should be reduced in the design. The results of this study could provide a guidance for the optimization design of the metal matrix microencapsulated fuels.