The invention provides a nitrogen-containing heteroaryl lactic acid derivative. The nitrogen-containing heteroaryl lactic acid derivative comprises a compound as an active component represented by the formula 3 as shown in the specification or acceptable salts thereof, wherein R<1>, R<2>, R<3> and R<4> are hydrogen or C1-C40 aliphatic groups including methyl, ethyl, propyl, isopropyl, butyl, benzyl and trifluoromethyl or C6-C60 aromatic groups including phenyl, substituted phenyl, 1-naphthyl, 2-naphthyl, or alkoxy, hydroxy, nitro, amino, fluoro, chloro, bromo and iodo. According to the preparation method, a nitrogen-containing heteroaryl compound is adopted as a nucleophilic reagent, a carbonyl compound is adopted as an electrophilic reagent, an iron source is adopted as a catalyst, and in the presence of an organic solvent, through activation of sp<3>C-H, the nitrogen-containing heteroaryl lactic acid derivative is directly synthesized by virtue of one-step reaction. The method has one hundred percent of atom economy and all atoms in the raw material are converted to the product; the method has the advantage of mild reaction conditions, is convenient to operate and is environment-friendly and has important application value.