The invention provides ingavrin and a method for detecting impurity of an ingavrin preparation. The method is a high-performance liquid chromatography, takes octadecylsilane chemically bonded silica or octa-silane chemically bonded silica as a chromatographic column of a filler, takes a mixed solvent of an organic phase and a water phase as a mobile phase for gradient elution, and ten impurities in ingavrin and its preparation can be determined. The method has the advantages of low process and low cost, by employing a gradient elution method, ten impurities in ingavrin and its preparation can be effectively determined and separated, the detection method is scientific, reasonable and objective, so that the ingavrin quality can be better controlled.