At present, there is no specific and effective antiviral therapy.In this study, an open, prospective/retrospective, randomized controlled cohort study was designed to compare the efficacy of different hormone doses in the treatment of 2019-nCoV severe Pneumonia.This study explores effective treatment programs for 2019-nCoV severe pneumonia and provides a reliable evidence-based basis for the treatment.

Inclusion Criteria:

1.Meet the definition of severe pneumonia(Comply with any of the followings):

1. Shortness of breath,RR≥30 bpm;
2. In a resting state:SPO2≤93%;
3. PaO2/FiO2≤300mmHg.

2.2019-nCoV nucleic acid test was positive.

3.CT of the lung conformed to the manifestation of viral pneumonia.

Exclusion Criteria:

1. dying state (i.e. survival time is less than 24 hours);
2. progressive malignant tumor with life expectancy less than 6 months;
3. immunosuppressive status(patients using immunosuppressants or chemotherapeutic drugs)
4. underlying diseases requiring long-term glucocorticoid treatment in the past 6 months or short-term glucocorticoid therapy in the past 4 weeks;
5. pregnancy
6. patients with glucocorticoid taboos