TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The Al-Ti-Mg composite oxide carrier comprises (wt.%), based on total quantity of the first section catalyst, aluminum oxide (Al2O3) (60-75), titanium dioxide (TiO2) (5-15), and magnesium oxide (MgO) (3-10). The Al-Ti-Mg composite oxide is a product obtained by depositing aluminum salt, titanium salt and magnesium salt step by step. The Al-Ti composite oxide binder comprises (wt.%), based on total quantity of the second section catalyst, Al2O3 (15-40) and TiO2 (2-15). It is a product obtained by depositing aluminum salt and titanium salt step by step. The mole ratio of silicon dioxide (SiO2)/Al2O3 of the HZSM-5 zeolite is 30-60. The inorganic acid is nitric acid or hydrochloric acid.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The mixed acid modification includes stirring and pickling the product of hydrothermal treatment for 1-4 hours at 70-90 degrees C by using a mixed acid whose pH value is 1-4, where liquid and solid ratio between the mixed acid and the product of hydrothermal treatment is 5-10 mL/g. When the inferior gasoline is heavy distillate gasoline obtained by cutting inferior full-distillate catalytic gasoline at 50-90 degrees C, the method comprises mixing a product of the heavy distillate gasoline modified by the reaction of the second section with light distillate gasoline obtained by cutting the inferior full-distillate catalytic gasoline at 50-90 degrees C, thus obtaining clean gasoline. Preferred Condition: The reaction condition of the inferior gasoline in the first section of the reaction region includes a hydrogen partial pressure of 1-3 MPa, a liquid volume space velocity of 3-6 h-1, a reaction temperature of 200-300 degrees C, and a volume ratio of hydrogen and gasoline of 200-500. The reaction condition of the reaction effusion of the first section in the second section of the reaction region includes a hydrogen partial pressure of 1-3 MPa, a liquid volume space velocity of 1-3 h-1, a reaction temperature of 350-410 degrees C, and a volume ratio of hydrogen and gasoline of 200-500. The condition for hydrothermal treatment of modified HZSM-5 zeolite in the second section catalyst includes a temperature of 560-700 degrees C, an air speed of vapor of 1-4 h-1, and a treatment time of 15-50 minutes. Preferred Component: In the mixed acid for pickling, the mole ratio between the organic acid and the inorganic acid is 5-20:1. The organic acid is acetic acid, citric acid, oxalic acid, or tartaric acid. The inferior gasoline is inferior full-distillate gasoline. It comprises one or a mixture comprising catalytic gasoline, burned gasoline, catalytic pyrolysis gasoline, thermal cracking gasoline or steam cracking gasoline.