The present invention belongs to the field of pharmaceutical chemical intermediates and related chemical technologies, and provides a method for preparing a green quinoline compound. An N-substituted aniline derivative is used as a raw material, and is reacted with a phenylacetylene or a styrene derivative at 80癈-160癈 for 24 hours in the presence of a Br鴑sted acid catalyst and an oxidant and in the absence of a solvent, to give a quinoline compound. The present invention is simple to operate and environmentally friendly, has mild conditions and potential for industrialization, and obtains the quinoline compound in higher yields. The quinoline compound synthesized by the method can be further functionalized to obtain various compounds applicable to the research and development of natural products, functional materials, and fine chemicals.