Birth cohort study has played an important role in exploring the effect of exposures in early life on long-term health of offspring. With the rapid increase of problems of reproductive health among couples at childbearing age, the assisted reproductive technology (ART) has been widely introduced into clinical practice. However, the influences of ART on long-term outcomes of mothers and infants have not been fully studied. In 2016, the China National Birth Cohort (CNBC), a multicenter prospective cohort study recruiting families with ART-conceived pregnancies and spontaneous-conceived pregnancies simultaneously was launched officially. By June 30, 2021, a total of 72 000 families covering 39 000 ART- pregnancies and 33 000 spontaneous- pregnancies have been recruited in the study, their information and biological samples were collected at multiple time points, i.e., before assisted reproductive treatment, in embryo transfer period, in first, second and third trimesters, at delivery, and at 42 days after birth, 6 months, 1 year old and 3 years old. The main objectives of this study are to assess the development and health of offspring born after ART treatment, identify risk factors associated with adverse birth outcomes and childhood diseases and provide scientific basis for the strategies to improve the quality of new birth population. This paper will give a brief introduction to the establishment and research progress of CNBC.