Abstract: Starting with the bottom logic of "moving for living" and modern lifestyle of "de-physical-activity", the practical significance of physical activity epidemiology is explored. Based on the research paradigm of physical activity epidemiology(PAE), the classic cases of employees of London transport executive and postal system are traced back.The disciplinary system of physical activity epidemiology has therefore been established from research subject, theoretical framework, and research paradigm.The development trends is also indicated in the aspects of movement program, research methods and physiologic-biological mechanism, showing the internal relations among physical activity levels, health risk elements and active life styles.