To determine the differential proteomic expressions in human L-02 liver cells induced by varying concentrations of trichloroethylene (TCE), comparative proteomic analysis was performed on human L-02 liver cells which were treated with varying concentrations of TCE. According to the result of MTT test, we designed four different groups, in which the cells were treated with 0 microM (control group), 3, 10 or 40 microM TCE for 24 h, respectively. Comparative analysis of approximately 800 spots resolved by two-dimensional gel electrophoresis (2DE) in the soluble proteomes of L-02 cells from the four different groups resulted in 10 differential proteins. To identify the differential spots, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) was carried out; if the results from the tool were insufficient, tandem MS (MALDI-TOF-TOF-MS) was then performed. The raw data of peptide mass fingerprints (PMFs) and MS/MS spectra were searched against the IPI human data base for exact matches. Then western blot was employed to verify the result of proteomic analysis, the following result confirmed that the results of proteomic analysis were reliable. These results might provide an insight into the underlying mechanism of TCE intoxication and find biological markers for diagnosis and therapy of TCE-induced diseases.