Electron capture dynamics of SO2-H2O (Ar)(n) complexes (n = 0-2) have been investigated by means of direct ab initio molecular dynamics (MD) method in order to elucidate the effects of solvent argon on the reaction dynamics of SO2-H2O. The neutral complex of SO2-H2O has a C-s symmetry, and the sulfur of SO2 interacts with the oxygen of H2O with an eclipsed form. In the SO2-H2O(Ar)(n) complexes, the dipole of H2O interacts with the argon atoms in the most stable structure. Following the electron capture of the complex SO2-H2O, the complex anion SO2-(H2O) is dissociated directly into SO2- + H2O. On the other hand, the electron capture of SO2(H2O)(Ar)(n) argon complex (n = 1-2) leads to the anion-water complex SO2- (H2O) because the collision of H2O with the Ar atom causes a rebound of H2O from Ar atom to the SO2- anion. The argon solvent enhanced the SO2-(H2O) complex formation. The reaction mechanism of SO2(H2O) in the participation of argon atoms was discussed on the basis of the present results.