In this work, BiFeO3 thin films were deposited on FTO substrate by inkjet printing through a sol-gel route. The effect of annealing atmosphere (air, N-2, O-2, we air, wet O-2, wet N-2) on the microstructure and surface property of the BiFeO 3 thin films was characterized by XRD and FE-SEM at room temperature. Ferroelectric properties and leakage currents were investigated in detail to understand the link between annealing atmosphere and thin films quality. Pure perovskite phase and dense microstructure can be promised by ink-jet printing and the thickness of the films can be controlled by the number of layers printed. On the other hand, attributed to the pure BiFeO3 phase and better surface topography, the films annealed in wet air showed the lowest leakage current density and best ferroelectric properties. It was proposed that less Fe2+ resulted from the annealing process is the key for the better ferroelectric properties.