Based on ArS2 analysis potential function, which was calculated using ab initio MP2/6-31+G method and multi-body expansion theory, the dynamic proces s has been studied. The results indicated that the restraint of Ar and S2 due to physical adsorption, and the reaction of Ar and S2 is pri marily non-elasticity collision at a serial set of energies. Through analysis of inelastic collision products, it is shown that Ar atom can excite S2 (Ｘ3Σ－g) to S2(B3Σ－u) gradually.