Objective To report a case of severe coronavirus disease 2019 (COVID-19) that had been successfully treated with glucocorticoid and intravenous immunoglobulin therapy. Methods and results The patient was a healthcare provider in Wuhan City who was taking care of COVID-19 patients before the onset of the disease. He started to cough with a little white sticky sputum on January 16, 2020 and had a fever on January 22 (up to 38.5℃) before admission. CT results showed mild exudation in both lungs. Oral oseltamivir and intravenous moxifloxacin, cefoperazone and sulbactam sodium were given in addition to nutritional support. On January 26, the patient had chest tightness and shortness of breath. A swab test was positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid, and chest CT results showed moderate exudation in both lungs. On January 28, shortness of breath worsened and intravenous methylprednisolone (40 mg, qd) and immunoglobulin (10 g, qd) were given. On January 30, shortness of breath further worsened; he had a body temperature of 40.7℃, pulse oxygen saturation (SpO₂) of 83% with oxygen inhalation at 10 L/min, and lymphocyte count of 0.5×10⁹/L. The dose of methylprednisolone and immunoglobulin were adjusted to 40 mg, q12h and 20 g, qd, respectively. Subcutaneous injection of thymalfasin (1.6 mg, qd) was added. Then the body temperature returned to normal, and symptoms such as chest tightness and shortness of breath were gradually improved. On January 31, SpO₂ was 88% with oxygen inhalation at 10 L/min and a chest CT results revealed large amount of exudation in both lungs. On February 2, SpO₂ was 95% with oxygen inhalation at 5 L/min and the dose of methylprednisolone was then gradually reduced. A chest CT results on February 3 revealed improved lung inflammation, and a throat swab on February 4 and 9 was negative for SARS-CoV-2 nucleic acid. Conclusion Glucocorticoid should be used with caution in patients with early and mild COVID-19. However, appropriate dosage of glucocorticoid can be used to modulate lung inflammation in patients with decompensated respiratory failure. Additionally, large dose of immunoglobulin can be given if necessary.