High purity of titanium tin carbide (Ti2SnC) powder was fabricated by pressureless sintering two types of mixtures of Ti/Sn/C and Ti/Sn/TiC powders under different conditions. A bimodal microstructure of Ti2SnC with plate-like and rod-like forms was first observed, which is determined by the grain growth rate in different planes, the C particle's size, and the growth environment. Based on the microstructure observation, a reaction model was proposed to understand the reaction mechanism for the formation of Ti2SnC. Further investigation of the thermal stability of Ti2SnC demonstrates that Ti2SnC decomposes to TiC and Sn in vacuum atmosphere at 1250 degrees C.