In recent years, BiCuSeO oxyselenides have been developed as a promising thermoelectric material. In this article, PbxBi1−xCu1−ySeO (x = y = 0, 0.02, 0.04, 0.06, and 0.08) are prepared by solid‐state reaction method and spark plasma sintering (SPS), and the combinatorial effects of Pb doping and Cu deficiencies on thermoelectric properties are investigated systematically. The transport properties are significantly enhanced due to the optimized carrier density, majorly contributing to the promotion of ZT values. As a result, the maximum ZT of 0.77 at 873 K and average ZT (from 300 to 873 K) of 0.50 are obtained for Pb0.06Bi0.94Cu0.94SeO sample. The values are 0.4 and 1.2 times, respectively, higher than that of pristine sample.