The application of molecular biological technique provides opportunity to pancreatic cancer patients since the cancer is resistant to routine treatment. Clarifying the molecular mechanism in the genesis and development of pancreatic cancer is the first thing to do. Recent researches found that there were different signaling pathways activated in different stages of pancreatic cancer. The important signal pathways included mitosis pathways, growth factor pathways, developing pathways and mucin pathways. This article will review the relationship between molecular pathways and pancreatic cancer.