The industrial development and growing human activities have caused the increasing energy consumption and waste heat emission. Thermoelectric (TE) generator, which is capable of converting the undesired waste heat into the precious electricity through Seebeck effect, has been considered as one of the sustainability solutions. Cubic GeTe featured with high electrical and thermal conductivity is targeted in this study, and the thermal/electrical transport properties are tuned by the fluctuations in mass and phase region, with respect to the changing Sb doping amounts. The information of phase stability, microstructures and thermodynamic behaviors are illustrated by the isothermal section and liqiudus projection of ternary Ge-Te-Sb system, on the basis of the thermally-equilibrated or the as-quenched alloys. Several series of Sb-incorporated GeTe are grown by the Bridgman method, and the thermoelectric transport properties are found to be correlated strongly with the starting compositions and secondary phases.