Methylammonium bismuth iodide (MA(3)Bi(2)I(9)) has been recently investigated as a light absorber in lead-free perovskite solar cells. However, the MA(3)Bi(2)I(9) film fabricated via conventional one-step spin coating methods usually has poor surface morphology, limiting the device performance. Herein, a cation displacement approach was employed for the fabrication of MA(3)Bi(2)I(9) film, where (CH3CH2CH2NH3)(3)Bi2I9 (PA(3)Bi(2)I(9)) film was first deposited from a solution containing CH3CH2CH2NH3I and BiI3 and then transformed into MA(3)Bi(2)I(9) film in a methylamine atmosphere. With the technique, the MA(3)Bi(2)I(9) film was realized with smooth, uniform, and compact surface morphology. Using the MA(3)Bi(2)I(9) film as a light absorber, a mesoporous photovoltaic device was fabricated with a power conversion efficiency of 0.33%, which is about two times higher than the value (0.15%) obtained for the one-step spin coating MA(3)Bi(2)I(9) device. Moreover, the facile film fabrication strategy utilized in this work paves the way for high reproducibility of lead-free organic-inorganic halide films and devices.