Since the completion of the Human Genome Project in 2003 and the announcement of 
the Precision Medicine Initiative by U.S. President Barack Obama in January 
2015, human beings have initially completed the " three steps" of " genomics to 
biology, genomics to health as well as genomics to society". As a new 
inter-discipline, the emergence and development of precision medicine have 
relied on the support and promotion from biological science, basic medicine, 
clinical medicine, epidemiology, statistics, sociology and information science, 
etc. Meanwhile, molecular epidemiology is considered to be the core power to 
promote precision medical as a cross discipline of epidemiology and molecular 
biology. This article is based on the characteristics and research progress of 
medicine and molecular epidemiology respectively, focusing on the contribution 
and significance of molecular epidemiology to precision medicine, and exploring 
the possible opportunities and challenges in the future.