Proteome means the total proteins expressed by the genome in a cell or tissue. Two-dimensional electrophoresis (2-DE) is now the most powerful separating technique and the key separation method used in proteome. Peptide mass fingerprinting (PMF) is becoming a widely used and vastly developed technique for protein identification in 2-D gels. In this research, a systematic method to identify the proteins in polyacrylamide gels by PMF was developed. Proteins were digested in-gel by enzyme and the masses of generated peptides were measured by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). The data obtained from PMF were used in protein database search and the protein identification. The proteins from human lung cancer cells isolated by 2-DE were subjected to identification by the PMF method developed in this work. Three spots of proteins in gel were identified as G3P2_HUMAN, UBL1_ HUMAN and TPIS_HUMAN.