The recent emergence of a novel coronavirus (2019-nCoV), which caused an outbreak of unusual viral pneumonia in tens of people in Wuhan, a central city of China, restated the risk of coronaviruses posed to public health. In this mini-review, we give a brief introduction of the general features of coronaviruses and describe various diseases caused by different coronaviruses in humans and animals. This review will help understand the biology and potential risk of coronaviruses that exist in richness in wildlife such as bats.