Nb2O5 and Bi2O3 powders were dispersed by anionic dispersants separately and followed by optimized colloidal processing steps to obtain the best mixing results. The influences of the dispersants were investigated by the measurements of zeta‐potential, dissolution of cations, adsorption of the dispersant, and size distribution of the suspensions. The homogeneity of sintered samples was checked by quantitative EDS and analyzed by Student's (t)‐statistics. Detailed analyses on surface properties of powder to microstructure and electric conductivity are reported. The best 21 mol% Nb‐doped Bi2O3 (B21N) has the conductivity improvement 1.0–5.3 times better than comparable cases in the temperature range of 450°–700°C.