 This study examined the effectiveness of a shift base, 3-5 micapto, 1, 3, 4, 5 years old, 2, YL, imino, indolin, 2-1, MTIO, to prevent mild steel corrosion in hydrochloric acid. The results showed that 0.5 mm MTIO exhibited a satisfactory inhibitor efficiency of 96.9% at 303K. The MTIO molecules physically and chemically adsorbed onto the mild steel surface, forming a compact protective film due to the presence of a thiazol ring in the MTIO structure. Theoretical calculations were used to further understand the anti-corrosion performance and mechanism of inhibition. This article was authored by Nadia Beti, Ahmed Al-Amyri, Walid Khalid Al-Azawi and others.