Thin films of p-type Bi0.52Sb1.48Te3 + 3% Te were deposited on glass substrates by flash evaporation. X-ray diffraction and field-emission scanning electron microscopy were performed to characterize the thin films, and the effects of preparation and annealing parameters on the thermoelectric properties were investigated. It was shown that the power factors of the films increased with increasing deposition temperature. Annealing the as-deposited films improved the power factors when the annealing time was less than 90 min and the annealing temperature was lower than 250°C. A maximum power factor of 10.66 μW cm−1 K−2 was obtained when the film was deposited at 200°C and annealed at 250°C for 60 min.