As a powerful analysis approach,matrix assisted laser desorption/ionization mass spectrometry(MALDI-MS) has attracted considerable attention in biomolecular analysis.However,this approach could hardly be used in the detection for samples with molecular mass lower than 500.In this work,poly (styrene-co-maleic anhydride) microbead@silver nanoshell(PSMA@Ag) composite microbeads with core-shell structure were synthesized using a polydopamine modification method.FT-IR results demonstrated the successful coating of polydopamine(PDA).SEM images along with UV-Vis results indicated that Ag nanoparticles were uniformly modified onto the surface of PSMA microbeads.The prepared PSMA@Ag microbeads were directly applied in matrix assisted laser desorption/ionization mass spectrometry,successfully detecting 2 pmol proline (Mw=115) and 1 pmol serine(Mw=105) in 0.5 μL sample,respectively.This work verified the positive effect of PSMA@Ag microbeads in MALDI-MS laser desorption/ionization process,and provided a promising route for MALDI analysis of the biomolecules with low molecular mass.