A novel coronavirus, SARS-CoV-2, was identified in Wuhan, China, and has caused a global pandemic. It shares the ACE2 receptor with SARS-CoV. This study used single-cell RNA sequencing to analyze ACE2 expression in normal human lung tissue. The results showed that ACE2 is mainly expressed in type II alveolar cells (AT2), which also express genes that promote viral entry, replication, and transmission. These findings suggest that AT2 cells are particularly susceptible to SARS-CoV-2 infection. The study also found that ACE2-expressing AT2 cells have enriched viral-related biological processes, including viral replication and transmission. However, the study's small sample size limits the generalizability of the findings. The research highlights the importance of ACE2 in SARS-CoV-2 infection and suggests that targeting AT2 cells could be a potential therapeutic strategy. The study also notes that ACE2 expression varies among individuals, which may affect susceptibility to SARS-CoV-2. Future studies with larger sample sizes are needed to confirm these findings and to better understand the role of ACE2 in SARS-CoV-2 infection. The study provides valuable insights into the pathogenesis of SARS-CoV-2 and may inform the development of new therapeutic strategies.A novel coronavirus, SARS-CoV-2, was identified in Wuhan, China, and has caused a global pandemic. It shares the ACE2 receptor with SARS-CoV. This study used single-cell RNA sequencing to analyze ACE2 expression in normal human lung tissue. The results showed that ACE2 is mainly expressed in type II alveolar cells (AT2), which also express genes that promote viral entry, replication, and transmission. These findings suggest that AT2 cells are particularly susceptible to SARS-CoV-2 infection. The study also found that ACE2-expressing AT2 cells have enriched viral-related biological processes, including viral replication and transmission. However, the study's small sample size limits the generalizability of the findings. The research highlights the importance of ACE2 in SARS-CoV-2 infection and suggests that targeting AT2 cells could be a potential therapeutic strategy. The study also notes that ACE2 expression varies among individuals, which may affect susceptibility to SARS-CoV-2. Future studies with larger sample sizes are needed to confirm these findings and to better understand the role of ACE2 in SARS-CoV-2 infection. The study provides valuable insights into the pathogenesis of SARS-CoV-2 and may inform the development of new therapeutic strategies.