Coronavirus disease 2019 (COVID-19) is caused by infection with the 2019 novel coronavirus 2 (2019-nCoV, now referred to as SARS-CoV-2). COVID-19 has become a global pandemic since its outbreak at the end of Dec 2019. COVID-19 could lead to severe acute respiratory disease, especially to those who have reduced immunity. Binding of the viral Spike protein (S) to its receptor ACE2 (Angiotensin Converting Enzyme 2) on the surface of target cells has been proven to be key for virus entry and infection. Although ACE2 expression in the respiratory system is necessary for pneumonia infection by SARS-CoV-2, the regulation of ACE2 gene expression remains poorly investigated, especially for patients that are in pre-pathological conditions. Here, by analyzing The Gene Expression Omnibus (GEO) database, we investigated the expression regulation of ACE2 in various kinds of primary epithelial cells from the respiratory system after varies of respiratory viruses infection such as influenza A virus (IFV), respiratory syncytial virus (RSV) and human rhinovirus (hRV). Our analyses reveal that infection of multiple kinds of respiratory viruses or influenza vaccines greatly increased ACE2 expression, suggesting that respiratory viruses infection could represent a high risk factor for developing COVID-19. We also found that the regulatory effect of influenza A virus on ACE2 expression is associated with activation of the interferon beta-induced pathway and viral RNA-activated host response. Together, our data provide a theoretical framework for clinical classification for SARS-CoV-2 infection susceptibility and could be used for future prevention and therapy treatment for COVID-19.