The latest research shows that the spike-receptor binding domain (RBD) sequence of SARS-CoV-2 interacts with host receptor ACE2 and this RBD-ACE2 complex plays a key role in virus invasion and virulence. Based on the current research progress, the RBD-ACE2 complex is considered as a target for the treatment of coronavirus infection to block SARS-CoV-2 from entering host cells.