Pancreatic stellate cells (PSCs) are a type of pluripotent cells located around the pancreatic lobules and acinar units. PSCs are in a quiescent state in the normal pancreas. Under the stimulation of various pathophysiological conditions, PSCs will be activated, and activated PSCs can be transformed into an activated phenotype similar to myofibroblasts. Compared with the quiescent state, activated PSCs can proliferate and actively migrate, secrete a large amount of extracellular matrix, and participate in the regulation of the progression of the pancreatic cancer and chronic pancreatitis acting as an important component of the microenvironment of the diseased pancreas. At the same time, a large number of studies have clarified that PSCs have functional heterogeneity. Because of their cell markers and functional differences, they are divided into different cell subgroups, which can regulate the occurrence and development of pancreatic cancer alone or in collaboration. The exosomes derived from PSCs can promote the growth, proliferation and invasion of pancreatic cancer cells through information transfer and material exchange between cells, and thereby regulate the development of pancreatic cancer. In chronic pancreatitis, activated PSCs and their derived exosomes are important components that initiate and promote pancreatic fibrosis. Therefore, the research on the functional heterogeneity of PSCs and the derived exosomes may provide new strategies and methods for the treatment of pancreatic diseases.