Quinoline derivative preparation method

The present invention belongs to the technical field of medicine, and more particularly relates to a preparation method for a multiple sclerosis treatment drug intermediate quinoline derivative, wherein a compound represented by a formula II is treated in the presence of an alkali, and then acidification is performed by using an acid to obtain a compound represented by a formula I. According to the present invention, the used solvents are the low-toxicity solvent and water, the reaction conditions are mild, the operation is simple and controllable, and the method is suitable for large scale industrial production.