Aniline was introduced into a solution of tin halide perovskite precursor to interact with formamidinium iodide (FAI) through hydrogen bonding, which optimized the crystal orientation of the tin halide perovskite and contributed to the charge transport and structural stabilization. The lead-free tin halide perovskite solar cells achieved a power conversion efficiency of 12.04% together with a high open-circuit voltage of 788 mV.