Coronaviruses (CoVs) are a group of viruses that co-infect humans and other vertebrate animals. CoV infections affect the respiratory, gastrointestinal, liver, and central nervous systems of humans, livestock, birds, bats, mice, and many other wild animals [1,2,3]. For example, severe acute respiratory syndrome (SARS) in 2002 and the Middle East respiratory syndrome (MERS) in 2012 were both coronaviruses that transmitted from animals to humans [4,5]. The source of unexplained pneumonia was first discovered in Wuhan in Dec, 2019, and SARS-CoV-2, a new coronavirus, was isolated from the respiratory epithelium of patients. It belongs to a new evolutionary branch within the CoV. On Feb. 11th, 2020, the new coronavirus was officially renamed “SARS-CoV-2” from “2019-nCoV” [6]. The disease caused by SARS-CoV-2 was called “coronavirus disease 2019” (COVID-19) [7]. According to the data released by the National Health Commission of the People’s Republic of China, SARS-CoV-2 was most likely transmitted from wild bats to humans, and all the above three CoVs can transmit from person to person [8,9,10]. SARS-CoV-2 shares a highly similar gene sequence and behavior pattern with SARS-CoV [11]. This paper summarized the similarities and differences between SARS-CoV-2 and SARS-CoV, both of which cause major disease outbreaks in China and worldwide, which will provide comprehensive reference for epidemic prevention.