During the second half year of 2019, unexpected pandemic which was caused by a coronavirus attacked the earth, infecting 230 million people,according to the WHO data, taking 4.7 millions' life. The virus looks like the corona under the microscope of scientists,hence the name coronavirus. Coronavirus is widespread in the nature, and most of it are harmless. But COVID-19, also knonwn as SARS-Cov-II, is the third type of coronavirus bringing disasters to human being. The first one is SARS, and the second one is MERS.