Bi2Te3 and its based materials are the most commonly used thermoelectric materials, and it is fundamentally important to understand the interfacial reactions between Bi2Te3 and possible contact materials. Interfacial reactions between Bi2Te3 and Cu, In, Sn and Ni are systematically examined. Significant interfacial reactions are observed in all the Cu/Bi2Te3, In/Bi2Te3, Sn/Bi2Te3 and Ni/Bi2Te3 couples. Te compounds, Cu2-xTe, InTe, SnTe and NiTe, are formed in these couples, respectively. In the Cu/Bi2Te3 and Ni/Bi2Te3 couples, liquation phenomenon was observed at 300℃. Since the reaction products are primarily Te-compounds, it can be concluded that Te in the Bi2Te3 substrate reacted with the contact materials, and the excess Bi became molten at 300℃. In the Cu/Bi2Te3 couples, a metastable (Cu)x(Bi2Te3)1-x was formed in the early stage of the reaction, and the metastable phase decomposed later and formed the Cu2-xTe and liquid phases. Similar phenomenon is being investigated in the Ni/Bi2Te3 couples.