The Novel Coronavirus Disease 2019 (COVID-19) is caused by severe acute respiratory syndrome(SARS) coronavirus 2 (SARS-CoV-2) with main clinical manifestations of fever, dry cough, fatigue and other symptoms of upper respiratory tract infection. Severe patients have a rapidly progress of SARS, septic shock, metabolic acidosis difficultly to be corrected, coagulation dysfunction and multiple organ failure, etc. Epidemiological investigations in many countries have shown that olfactory dysfunction is one of the clinical symptoms of COVID-19, and even the initial symptom of some patients with COVID-19. This phenomenon indicates that the olfactory dysfunction plays an important role in the early diagnosis and clinical screening of COVID-19. This paper reviewed the epidemiology, prognosis and pathogenesis of olfactory disorders caused by COVID-19. The results showed that olfactory disorders mostly occurred in mild covid-19 patients, who had a good prognosis. At present, the pathogenesis of olfactory dysfunction caused by COVID-19 is still unclear. It is speculated that the mechanism of olfactory dysfunction caused by COVID-19 is similar to that of other respiratory viruses. It may be caused by nasal mucosa swelling, directly a virus damage to olfactory epithelium or olfactory pathway with a disorders of sensorineural smell, among which ACE2 and TMPRSS2 might play an important role.