The invention relates to the field of organic synthesis, and concretely relates to a preparation method of a 5-sulfonyl oxy-8-carboxamidoquinoline derivative, in particular to the method for preparing the 5-sulfonyl oxy-8-carboxamidoquinoline derivative by adopting 8-acetamido quinoline as a raw material. The method is characterized by comprising the steps of adopting trifluoroacetic acid iodobenzene as an oxidizing agent, carrying out C-H functionalization reaction on 8-carboxamidoquinoline and various different N,N'-disulphohydrazide compounds under metal-free catalysis, and obtaining a C5-site sulfonyl oxy substituted product. Compared with the document, the preparation method provided by the invention has the characteristics that the raw materials are easily obtained, the substrate adaption range is wide, the yield is high and the like.