Bismuth nanocrystals were embedded in amorphous Bi2O3 thin films grown under a nitrogen atmosphere at room temperature using pulsed laser deposition. As-grown Bi2O3-Bi thin films showed a high electrical conductivity of approximately 769 S/cm at 320 K, and the samples annealed in two steps at 200 and 300°C consisted of amorphous Bi2O3, bismuth nanocrystals in the crystallized β-Bi2O3 phase. The mixture phase of the bismuth nanocrystals and β-Bi2O3 enhanced the thermoelectric properties at room temperature. Samples annealed in two steps at 200 and 300°C showed an electrical conductivity of 833 S/cm, a Seebeck coefficient of –110 μV/K, a power factor of about 1.05 × 10−3 W/K2m. Formation of the bismuth nanocrystals in Bi2O3 thin films at low temperature made thermoelectric applications possible.