The early symptoms and laboratory findings of pancreatic cancer are nonspecific and the outcome of victims are poor. Currently surgical resection is the only means for cure. When pancreatic cancer is clinically suspected, it is usually non-resectable due to metastasis. So prevention and early diagnosis are especially important for pancreatic cancer. The risk factors of pancreatic cancer include male sex, old age, long-term smoking, coffee consumption, alcohol abuse, diabetes, chronic pancreatitis, hereditary factors, obesity, non-familial hypercholesterolemia, high caloric intake, and environmental factors. Many studies have indicated that pancreatic cancer is closely related to K-ras mutations, and patients with high susceptibility have a higher probability of K-ras mutations. This paper reviews the value of K-ras mutation in diagnosis of pancreatic cancer, K-ras mutation in pre-cancerous lesions, and the relation between high-risk factors and K-ras mutations.