This article uses four high boiling small molecule corrosion inhibitors, pyridine, quinoline, formamide, and trimethyl-1-pentynyl alcohol, to obtain the main corrosion inhibitor CT-220; Use phosphoric acid and arsenic acid as synergists. The indoor evaluation of corrosion inhibition performance was conducted at a temperature of 220 ℃. Under the condition of 15% HCl and 5% formic acid, with a main agent concentration of 5%, the corrosion rate of acid solution on P110 steel sheets is less than 15 g/m2 h; In the composite system of the main agent, acid solution, and other additives, under the conditions of 15% HCl and 5% formic acid, 220 ℃, and the main agent concentration of 5%, the corrosion rate of acid solution on P110 steel sheets is less than 20 g/m2 h. The electrochemical test results show that the acid solution composite system of the corrosion inhibitor composite system has a good corrosion inhibition effect. The corrosion rate reaches 0.7 mm/a under high acid concentration conditions, and the corrosion rate is far lower than the industry standard of 180 ℃. It is suitable for acid construction conditions with ultra-high temperature and high acid concentration.