The work aims to test the 2, 4-TDI monomer residue of the adhesive used in the drug packaging materials. The sample was extracted with acetonitrile and derivatived with 1, 2-pyridyl piperazine. Then, the derived product was tested with RP-HPLC, thus calculating the 2, 4-TDI monomer residue and investigating the methodology. The linear range of derivative was 0~1.2 μg/mL (linearly dependent coefficient R=0.9998, and number of linear fitting points n=7). The relative standard deviation (RSD) of precision was 1.52%. RSD of stability in 24 h was 2.51%. The mean recovery was 102.63% and the RSD of recovery was 1.79%. The method established is reliable, accurate, stable and specific, and can be used to test the content of derived product rapidly, thus calculating 2, 4-TDI monomer residue, and providing powerful support for the test of 2, 4-TDI monomer residue in the adhesive used by the drug packaging materials.