ACE2 and COVID-19: This article takes COVID-19 and SARS-CoV to invade targets as the main line, focuses on describing possible target organ damage, provides corresponding guidance for clinical diagnosis and treatment, explains the possible role of ACE2 in different organ damage, and provides the basis for follow-up, and Clinical research provides possible directions and ideas; ACE2 is not only a “gateway” for virus invasion but also a key substance that causes organ damage.