Before revision:  The evolution of coronavirus dependent on the alteration of conformation equilibrium is indicated. Finally, introduction of electric field to change the conformation potential barrier and how the conformation equilibriumdepends on temperature and humidity are briefly discussed .
After revision:  The comparison of the infectivity of SARS-CoV-2 with SARS-CoV-1 is made from the point of conformation equilibrium. Why the virus entrance takes priority in lower temperature and higher humidity is interpreted by the present theory. The conformational transition influenced by electromagnetic field is also discussed briefly .