In this study, Bi2Te3 was selected as a matrix material and an immiscible semiconductor material CdTe with a wider energy band gap was precipitated to form microstructures in it. For this purpose, a series of two-component composites (Bi2Te3)1-x/(CdTe)x, with x = 0.01, 0.05, 0.1, 0.15, 0.2 were prepared by melting, high speed rocking and quenching technique. The composition and microstructure of these two-component composites were examined by X-ray and SEM. Thermoelectric properties including Seebeck coefficient, electric resistivity, and thermal conductivity were measured from 30 K to 400 K. The compositional and temperature dependence of the microstructure and thermoelectric properties of (Bi2Te3)1-x/(CdTe)x composites were discussed. It is found that (Bi2Te3)0.99/(CdTe)0.01 exhibits a better thermoelectric performance than that of Bi2Te3 at elevated temperatures. The figure of merit (ZT) of (Bi2Te3)0.99/(CdTe)0.01 is about 0.64 at 400 K.