Abstract: TEM and HREM observations of the MoSi₂-SiC composite synthesised in situ reveal that large amounts of dislocations exist in the MoSi₂ matrix specially near the interfaces between MoSi₂ math and the SiC particles, and the SiC particles typically contain defects including twins and stacking faults. Nanoindentation investigation shows that there exists a gradient distribution of microhardness near the interface of MoSi₂/SiC. The microstructurd characters above can be attributed to the residue heat stress due to the CTE discrepancy between MoSi₂/SiC generated in the cooling process of the production.