Autophagy occurs in all types of eukaryotic cells, which has a rigid connection to normal development of cells and a variety of diseases. There are many molecular control elements and multiple signaling pathways involved in regulating autophagy. Autophagic cell death is considered as the type Ⅱ programmed cell death. There is a crosstalk between autophagy and apoptosis. Both of them participate in maintaining cell homeostasis and pathogenesis of certain diseases. The roles of autophagy in development, aging, tumor, neurodegenerative diseases and infectious diseases are reviewed.