Arsenic is a known human carcinogen widely distributed in the environment. Its contamination to the water source is associated with various human malignancies, including bladder cancer. Many studies have been shown that arsenic induced of gene transcription in vivo and in vitro. But the molecular mechanism of arsenic carcinogenesis is unknown. And there are a few studies have focused on arsenic caused alteration of protein pattern levels in vivo. In this study, we performed quantitative proteomic in rat uroepithelial cells using two-dimensional gel electrophoresis and Q-TOF Ultima-Micromass spectrometry analysis. Our results of 2-DE gel electrophoresis and mass spectrometry identified 13 downregulated and 9 upregulated proteins in untreated compared between treated with arsenic in rat uroepithelial cells. In addition, we were confirmed of the identities of proteins changed in vivo model with arsenic treatment by immunohistochemistry (IHC). These results illustrated a pattern of expression of differential proteins as the molecular markers in arsenic carcinogenesis.