Electrolyte has a crucial effect on the performance of electrodes in the process of the electrochemical reduction of carbon dioxide (ERC). In this work, we added common cations including SO₄^2-/HSO₄^-, NO₃^-,H₂PO₄^-/HPO₄^2-/PO₄^3-, Cl^-, Br^-, I^-, and CH₃COO^-) and common metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺) in a 0.1M NaHCO₃ aqueous solution to investigate the effects of their presence in electrolyte solution on the efficient ERC over single metallic Cu and Sn electrodes. The effect of these ions on the rate of the ERC, the distribution of the products, and the reaction mechanism of electroreduction of CO₂ over Cu and Sn electrodes in electrolyte solution were studied. According to experimental results, we will be able to choose the appropriate electrolyte to enhance electrocatalytic activity and stability, and improve the prediction selectivity of single metallic Cu and Sn catalysts.