In this comprehensive study, vegetable oil and polyamines were utilized as the foundational materials to synthesize vegetable oil-based amides through a meticulously controlled reaction process at a temperature of 180 ℃. The resulting synthesized products underwent rigorous analysis using infrared spectroscopy to confirm their chemical composition and structure. Following this, the vegetable oil-based amide was combined with hexamethylenetetramine and thiourea to evaluate the corrosion inhibition properties of the newly formulated inhibitor through the weight loss method . The outcomes of this investigation reveal that the corrosion inhibitors crafted from specific combinations, such as rapeseed oil paired with tetraethylenepentamine and formaldehyde, castor oil mixed with diethylenetriamine and formaldehyde, as well as hexamethylenetetramine and thiourea, exhibited remarkable synergistic effects. These innovative inhibitors demonstrated significant efficacy in mitigating the corrosion of A3 steel sheets by forming a dense protective film on the surface of A3 carbon steel, ultimately leading to a substantial enhancement in corrosion inhibition efficiency.