In this research, the electrochemical reduction of hydrogen process and the factors affecting the reduction potential have been studied in this research. The effect of acid concentration on the shifting of the volt-ampero-metric curves that express the reduction process and so its effect on both the reduction potential value of hydronium ions on drop mercury electrode, and the speed value of reduction reaction was studied. Then an amount of pyridine as organic substance was added to a specific volume of acid in a specific concentration to figure out the relationship between the amount of pyridine added and the cathode current of the reaction to find out the effect of added pyridine on the reaction speed and the relationship between the amount of added pyridine and the hydrogen reduction potential. Pyridine was added to amount of acid to study the effect of theaddition on the hydrogen reduction over potential.