SiC-fiber-reinforced γ-TiAl composite materials are promising for high-temperature structural applications owing to their excellent mechanical properties. However, the interfacial reaction of the composites during subsequent high-temperature processing and service is unstable as elements continue to diffuse around the interfacial reaction layer at high temperatures, and more interfacial reaction products are generated. When excessive brittle reaction products are generated, they have detrimental effects on the mechanical properties of the composites. Therefore, to better design and control the interfacial reaction, it is particularly important to study the formation and growth of the complex interfacial products of the composites. In this study, the formation mechanism of interfacial reaction products and thermal stability of SiC_f/TiAl composites were investigated by thermal exposure for different time. First, the SiC_f/TiAl composites were prepared by suction casting. Next, the specimens were examined by SEM and TEM to investigate the element diffusion and composition of the interfacial reaction products of the as-prepared composites. The interfacial reaction products in the as-prepared composites were mainly composed of a fine equiaxed TiC layer near a carbon layer and a coarse equiaxed TiC layer near a titanium alloy coating. Then, the thermal exposure was conducted at 800^oC to investigate the growth of the interfacial reaction products and thermal stability of the interfacial reaction layer. The results show that the thickness of the interfacial reaction layer increased with heat exposure time. Meanwhile, interfacial stratification was observed during the growth of the interface reaction layer. Further, the growth kinetics curve of the reaction layer was drew according to the thickness of the reaction layer with time, and the interfacial reaction growth rate was determined. According to the morphology and TEM analysis results, the interfacial reaction layer was divided into four layers after 200 h thermal exposure, unlike in the as-prepared state. From the fiber side to matrix side, fine-grained TiC, coarse-grained TiC, (Ti, Zr)₅Si₄, and Ti₃Sn + Ti₂AlC layers, respectively, were observed. Finally, the formation mechanism of the interfacial reaction products and element diffusion of SiC_f/TiAl composites under different conditions were studied, the interfacial stratification occurred during thermal exposure because some TiC participated during the formation of Ti₂AlC.