The present study focused on the synthesis of Bi-Te-Se-based thermoelectric powder by an oxide-reduction process. The phase structure and particle size of the synthesized powders were analyzed using XRD and FE-SEM. The synthesized powder was sintered by the spark plasma sintering method. The thermoelectric property of the sintered body was evaluated by measuring the Seebeck coefficient and specific electric resistivity. The Bi2Te2.7Se0.3 powder had been synthesized by a combination of mechanical milling, calcination and reduction processes using mixture of Bi2O3, TeO2 and SeO2 powders. The sintered body of the Bi2Te2.7Se0.3 powder synthesized by an oxide-reduction process showed n-type thermoelectric characteristics.