The invention discloses a preparation method and application of a Mannich base quaternary ammonium salt high-temperature resistant acidification corrosion inhibitor. The preparation method comprises the following steps that (1) amine indole, benzhydrylpiperidine, diphenylethylamine, dibenzylamine or diisopropanolamine is dissolved in an organic solvent; aldehyde substances of 3 (2 thienyl) benzaldehyde or cinnamyl aldehyde is slowly added; the mixture is put into a thermostat water bath pot; stirring reaction is performed for 1 to 3h at 60 to 80 DEG C; then, ketone substances of benzalacetone,acetone or 1,1 diphenylacetone are added; the PH value is regulated to 3 to 4; reaction is performed for 7 to 10h; cooling is performed to room temperature; reduced pressure distillation is performedfor removing solvents to obtain Mannich base; (2) Mannich base is dissolved in the organic solvent; quaternization reagents of chloromethyl naphthalene, benzyl chloride or triphenylchlorometha are added; reaction is performed for 14 to 16h at 70 to 90 DEG C; cooling is performed to room temperature; reduced pressure distillation is performed. The method is simple and feasible; raw materials are nontoxic; the safe and environment-friendly effects are achieved; the prepared acidification corrosion inhibitor has an obvious inhibition effect on acid corrosion of oil gas well carbon steel.