Abstract: AimTo identify protein spots on two dimentional protein electrophoresis (2DE) by post-source decay (PSD) technique associated with library search. MethodsThe PSD-MALDI-TOF-MS method was set up by a segment of ACTH and a peptide digested by trypsin for TPA. ResultsTwo unknown protein spots on 2DE were identified as 40S ribosomal protein S12 and dnaK suppressor protein separately by established PSD-MALDI-TOF-MS method. ConclusionPSD technique has greater application prospects in peoteomics.