The corrosion of N80 steel is important task in the chemical industry. The corrosion inhibitor was effectively way to protect the metal material from the corrosion attacks. In the present work, the new imidazole derivate was introduced for mild steel. The 3a,6a-di-p-tolyltetrahydroimidazo[4,5-d]imidazole-2,5(1H,3H)-dithione was selected as a potential corrosion inhibitor for N80 steel in the 0.5 M H2SO4. The inhibition properties of 3a,6a-di-p-tolyltetrahydroimidazo[4,5-d]imidazole-2,5(1H,3H)-dithione was investigated by the electrochemical method. The obtained results confirmed that the inhibition effectiveness for this inhibitor was 97,98 % at 200 mg/L.