Wide-bandgap perovskite stannates are of interest for the emergent all-oxide transparent electronic devices due to their unparalleled room temperature electron mobility. Considering the advantage of amorphous material in integrating with non-semiconductor platforms, we herein reported the optical and electronic properties in the prototypical stannate, amorphous barium stannate (BaSnO3) thin films, which were deposited at room temperature and annealed at various temperatures. Despite remaining amorphous status, with increasing the annealing temperature, the defect level within amorphous BaSnO3 thin films could be suppressed.