The Healthy Zhejiang Million Population Cohort Project obtains information on population health and diseases through large-scale population survey, physical examination and follow-up, collects health-related information such as environment, explores the causes of key diseases, and provides a basis for scientifically formulating prevention and control strategies for chronic diseases. With the rapid economic development and social transformation in China, the spectrum of diseases that mainly affect the health of our population has shifted from traditional infectious diseases to chronic non-communicable diseases such as tumors, cardiovascular diseases and diabetes. Carrying out cohort study is of great social significance for further promoting the accurate prevention and control of chronic diseases, promoting the health of the population and better serving the healthy construction of Zhejiang.