We investigate NLTE formation of the Ba II λ 455.4 nm resonance line in the solar spectrum for three one-dimensional and one hydrodynamic three-dimensional atmospheric models. Sensitivity of the line profile to atomic parameters, micro- and macroturbulent velocities, oscillator strength uncertainties, and barium abundance were studied. It is shown that line wings are most sensitive to the value of the van der Waals broadening constant. Another important parameter is the barium abundance. The barium abundance is derived assuming NLTE. We found that A_Ba = 2.16 which is in good agreement with recent results. The influence of granular convective motions on the line profile shape was studied. Granular and intergranular line profiles are very asymmetrical and have different shapes. It is shown that if NLTE effects and granular structure of the solar atmosphere are taken into account, good agreement between theoretical and observed profiles can be reached.