1. The patient signed an informed consent form to participate in the study of convalescent plasma therapy, 2. patient aged >=18 years old, 3. COVID-19 patients diagnosed by PCR, 4. Nucleic acid positive within 72 hours before blood transfusion, 5. Pneumonia confirmed by imaging, 6. Hospitalization for the following reason: Fever: axillary temperature>=36.7 degree C, or oral temperature>=38.0 degree C, or anal or ear temperature=38.6 ? And respiratory rate> 24 beats / min or cough (at least one of the two), 7. There are severe clinical warning indicators: such as a progressive decrease in peripheral blood lymphocytes, a progressive increase in peripheral blood inflammatory factors, a progressive increase in lactic acid, and rapid progress of lung lesions in the short term, et al. 8. Accept random grouping into any group, 9. The patient was hospitalized before the end of the clinical study. 10. Willing to participate in all necessary research directions and be able to participate in follow-up, 11. During the period of participating in this study, they will no longer participate in clinical trials such as other antiviral drugs.

1. The patient signed an informed consent form to participate in the study of convalescent plasma therapy, 2. patient aged >=18 years old, 3. COVID-19 patients diagnosed by PCR, 4. Nucleic acid positive within 72 hours before blood transfusion, 5. Pneumonia confirmed by imaging, 6. Hospitalization for the following reason: Fever: axillary temperature>=36.7 degree C, or oral temperature>=38.0 degree C, or anal or ear temperature=38.6 ? And respiratory rate> 24 beats / min or cough (at least one of the two), 7. There are severe clinical warning indicators: such as a progressive decrease in peripheral blood lymphocytes, a progressive increase in peripheral blood inflammatory factors, a progressive increase in lactic acid, and rapid progress of lung lesions in the short term, et al. 8. Accept random grouping into any group, 9. The patient was hospitalized before the end of the clinical study. 10. Willing to participate in all necessary research directions and be able to participate in follow-up, 11. During the period of participating in this study, they will no longer participate in clinical trials such as other antiviral drugs.