The structure and dissociation energy of the ground state of ArH+ are calculated using QCISD（T）/ Aug-CC-pVTZ method. Based on the theory of atomic and molecular statics，the reasonable dissociation limit for the ground state （1Σ+） of ArH+ is derived. The potential energy curve and relevant optical constants of this state are obtained by least square fitting to the Murrell-Sorbie function. All calculation results are in good agreement with the experimental data.