Abstract: Aging is an unavoidable problem that has puzzled scientists for years. The programming theory and the damage or error theory are representatives of the modern mainstream biological theories on human aging. With the continuous improvement of medicine, a variety of novel aging theories such as the microcirculation theory and the telomerase theory have emerged, which enrich the research perspectives in this field. But the existing theories are still not good enough to explain the process of aging. Many theories are related to each other in a complex way. The research and test of various aging theories can promote the understanding of the aging mechanism and benefit human beings.

Key words: aging; lifespan; mechanism