Objective To identify the different proteins of pancreatic cancer with and without diabetes mellitus (DM) ,so as to provide some clues for understanding the molecular mechanisms of DM in the development .of pancreatic cancer. Methods Samples were divided into pancreatic cancer with or without DM and their normal adjacent tissue with 5 each. The protein expression profiles were analyzed using 2-DE in combination with MALDI-TOF/TOF MS/MS. Western blot was used to verify the expression of a candidate protein CapG. Results Seven proteins were obviously up-regulated in pancreatic cancer with DM(P＜0.05). These proteins were involved in cell motility, metabolism, oxidative stress, etc. Additionally, CapG implicated a functional contribution of cancer invasion and metastasis. Conclusion The results also provide evidence to support the hypothesis that DM plays an important role in the development of pancreatic cancer.