Cellular autophagy not only plays a pivotal role in maintaining cellular homeostasis and promoting metabolism, but also has a close relationship with viral infections, therefore, cellular autophagy plays a crucial role in the human body. 1. The excess or damaged cytoplasm and organelles in the cell are wrapped by vesicles to form autophagosomes, which can fuse with lysosomes to form autophagic lysosomes to degrade their wrapped contents to realize cell homeostasis and cell self-renewal. 2. Stress conditions such as starvation, high temperature and hypoxia can also induce autophagy, which provides nutrients and energy for cellular activities by degrading macromolecular substances and organelles. 3. The life cycle of viral cell infection can cause cells to undergo autophagy. Autophagy has both positive and negative effects in viral infection: on the one hand, autophagy resists viral infection by degrading viral particles or activating the body’s immune defense system; on the other hand, autophagy is hijacked by viruses to promote viral replication. In addition, cellular autophagy is closely related to senescence, and autophagy can contribute to the progression of senescence as the level of autophagy decreases in senescent cells.