Essential trace element selenium (Se) exerts its biological functions in vivo mainly through selenoproteins.Thus highly sensitive detection of Se-containing trace proteins is the key step toward the confirmation of selenoproteins predicted bioinformatically from genomes or separated electrophoretically in the study of selenoproteomics.This review mainly describes the principle of a new technique of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS),which has been fast developed in recent years,and its application to the detection of Se in proteins separated by gel electrophoresis.The paper also summarizes the progress of mass spectrometry in the identification and characterization of Se-containing proteins after gel electrophoresis,including the detection of Se-containing peptides by ICP-MS hyphenated with either capillary high performance liquid chromatography or nano HPLC,the identification of Se-containing proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,and the characterization and confirmation of selenoproteins by nano HPLC-electrospray tandem mass spectrometry.Problems presented in those methods are also discussed in this paper for further study.