Thousands of people across many nations lost their lives due to COVID-19. This disease is caused by a novel coronavirus named SARS-CoV-2. Besides, we always have another massive threat. It is obesity, which causes about 2.8 million deaths each year across the globe. This pandemic has just highlighted obesity and its related complications. Evidence shows that obesity is likely to cause the development of vitamin D deficiency. Moreover, inadequate Vitamin D level is independently associated with the aged and other diseases. To date, there is still no specific treatment or prevention for the SARS-CoV-2. Emerging evidence indicates that vitamin D has potential roles in the immune response against enveloped viruses including SAR-CoV-2. Optimal dosage is probably determined by the vitamin D receptor gene polymorphism. The likelihood that vitamin D may offer a potential strategy against COVID-19 should be taken into account.