Abstract: The reasonable dissociation limit for the ground state of BeCl (X2Σ+) is determined based on the atomic and molecular reaction statistics.The equilibrium geometry,harmonic frequency and dissociation energy about the state have been accurately calculated at the B3LYP/cc-pVQZ level of theory.The potential energy curves for BeCl(X2Σ+) are calculated and fitted to the Murrell-Sorbie function.Then the spectroscopic constants (De,Be,αe,ωeχe) are evaluated and there is a good accord with the experiments.