1. The age at the time of signing the informed consent is >= 18 years old and <= 75 years old, both male and female, 2. The change of typical viral pneumonia in lung was detected by RT-PCR test of novel coronavirus nucleic acids or lung CT, 3. SaO2 / SpO2 <= 94% or pa02 / fi02 ratio < 300mghg at room temperature at admission, 4. Onset <=12 days, 5. Willing to participate in the trial and randomly assigned to any treatment group, 6. Cannot participate in another experiment during the study period.

1. The age at the time of signing the informed consent is >= 18 years old and <= 75 years old, both male and female, 2. The change of typical viral pneumonia in lung was detected by RT-PCR test of novel coronavirus nucleic acids or lung CT, 3. SaO2 / SpO2 <= 94% or pa02 / fi02 ratio < 300mghg at room temperature at admission, 4. Onset <=12 days, 5. Willing to participate in the trial and randomly assigned to any treatment group, 6. Cannot participate in another experiment during the study period.