The invention discloses a Pb<2+> antigen and a corresponding monoclonal antibody, and also provides a method for preparing the same. The preparation method comprises the following steps of: chelating Pb<2+> with a chelating agent p-NH2-Bn-CHX-A''-DTPA; coupling glutaraldehyde with hemocyanin (KLH); performing ultra-filtration to obtain a full immunizing antigen (KLH-NH-Bn-CHX-A''-DTPA-Pb); merging splenic cells and myeloma cells of a mouse immunizing BALB/c; and screening a specific monoclonal antibody which has strong positive for BSA-NH-Bn-CHX-A''-DTPA-Pb and no cross reaction with BSA-NH-Bn-CHX-A''-DTPA and other various metal ions. The antibody can be used for developing ELISA kits and test paper for detecting the Pb<2+> and has great application prospect.