The new coronavirus (2019-nCoV) in Wuhan has caused virus outbreaks in many provinces and cities in China, and several neighboring countries were also affected. In recent years, coronavirus several outbreaks around the world were reported, however researchers could not predict its onset. Coincidentally, the birthplace of another coronavirus (SARS-CoV) that causes serious public health problems is also in China. This review compares and analyzes the external environment, natural hosts, intermediate hosts, and susceptible populations when these two coronaviruses occurred. Based on the analysis results, we found that the 2019-nCov virus outbreak in Wuhan was not an accidental phenomenon, but a result of a combination of factors. At the same time, through the conclusions of these analyses, we will be able to get a glimpse of the trajectories of new coronaviruses and curb the virus outbreak in future.