Abstract: Corrosion inhibitors were synthesized by Mannich reaction using ketones, amines and aldehydes as raw materials and the process was monitored by in-situ infrared spectroscopy. The effect of various ketones and amines on the corrosion resistant performance of the synthesized inhibitors was investigated by static weight loss tests. Test results showed that the corrosion inhibitor synthesized by aromatic ketone, formaldehyde and aromatic amine was a kind of mixture with good corrosion resistant performance. When the corrosion medium was 15% HCl solution, system containing 1% of said inhibitor, at a system temperature of 90 ℃ and a contact time of 4 h, the corrosion rate was only 1.10 g/(m2?h), which indicated that the performance of this corrosion inhibitor met the requirement for first-class acidizing corrosion inhibitor in petroleum and natural gas trade standards.