Macroscopic and immunohistochemical observations were made to clarify the innervation of normal pancreatic tissues, and the clinicopathological and electron-microscopic findings of 33 cases of pancreatic cancer were obtained. The results showed that the innervation of both the head and the body of the pancreas mainly consisted of nerve fibers separated from the right celiac neuroganglion and the right half of the superior mesenteric arterial plexus. The pancreas was full of nerve fibers ending at acinar lobules, among which the adrenergic nerves commonly control the walls of blood vessels. Pancreatic cancer tends to be accompanied by invasion and metastasis along intra or extra-pancreatic nerves, and we found that the positive rates for invasion and metastasis were 73.33% and 60.00%, respectively. The follow-up study revealed that the nerve-invasion group had worse prognosis than the non-invasion group (P < 0.05). The approaches of the invasions of the nerves were as follows: (1) through the vessels of the perineurium; (2) through the perineurium; and (3) through the synaptic membrane of nerve endings. The invasion were a continuous process, often resulting in the destruction or even the disappearance of the normal structure of the nerve fibers. The above results suggest that there are plentiful vegetative nerves inside or outside the pancreas and that pancreatic cancers have a tendency of invading and metastasizing along or around nerves.