Abstract: Objective To analyze the differentially expressed proteins in metastatic colorectal carcinoma and provide clues for the molecular mechanisms of colorectal cancer metastasis. Methods A pair of colorectal carcinoma cell lines SW620 and SW480 with different metastatic potentials from the same parent cell lines were studied. The protein expression maps of the two cell lines were obtained and optimized using two-dimensional gel electrophoresis (2-DE), and the differentially expressed protein spots associated with metastasis were analyzed by Melanie ш software. Results The 2-DE expression maps of the two cell lines were well matched. The resolution of 2-DE was increased after using the nonlinear pH3-10 or overlapping narrow immobilized pH gradient strips, and 11 differentially expressed protein spots were identified after analysis using the software. Conclusions Nonlinear pH3-10 and overlapping narrow immobilized pH gradient strips have higher separation efficiency for protein in 2-DE. The differentially expressed proteins separated will be useful for identifying metastasis-associated proteins of colorectal carcinoma and for establishing 2-DE database of the metastatic colorectal carcinoma cell lines.