Relationships between corrosion inhibition efficiency of five kinds of mercapto-triazole inhibitors and their molecular electronic properties have been theoretically studied at the level of DFT/B3LYP with 6-31+G (d, p) base sets. Calculation results are discussed using linear regression analysis to determine the most effective parameters to establish inhibition efficiency. Regression equations find inhibition performances have a good linear relationship with EHOMO and (EHOMO-ELUMO). The adsorption energies are well accorded with the reported experimental results. Finally, this research may provide a theoretical inhibition performance prediction approach for new homologous inhibitors.