Coronaviruses (CoV) are enveloped viruses that possess a positive-sense single-stranded RNA genome 27～32?kb in length, belonging to the Coronaviridae family, the Nidovirales order. In recent years, coronaviruses have posed a great threat to human life and health. For example, in 2002 and 2012, severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) emerged and caused panic, respectiverly. In particular, a novel coronavirus designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019, has been epidemic so far worldwidely, seriously endangering human health and social order and arousing attention. So far, SARS-CoV-2 has evolved several variants. At present, the epidemic types are mainly Omicron family strains, and accompanying other variant strains. Meanwhile, SARS-CoV-2 is still in constant variation. Nowadays, the epidemic situation prevention and control of our country has entered the stage of “category B disease” with normalization prevention and control, whereas SARS-CoV-2 will still be an important public health issue in the future. In this review, the key mutations of various major strains of SARS-CoV-2 Omicron and their relationship with virus infectivity, pathogenicity, immune escape ability, and other characteristics were summarized, which can provide reference for the systematic understanding of SARS-CoV-2 evolution, transmission, and epidemic status.