This center intends to conduct a multicenter, randomized, placebo-controlled study to evaluate the effectiveness and safety of Nintedanib ethanesulfonate soft capsule in the treatment of pulmonary fibrosis in patients with moderate to severe COVID-19.

Inclusion Criteria:

• Subjects Age ≥ 18 Willing and able to provide written informed consent
• SARS-CoV-2 infection confirmed by PCR test/antigen dectection or positive serologies
• Time of illness onset ≥8 days
• Have findings consistent with interstitial lung disease found on CT scan
• Willing not use other investigational agents of anti-fibrosis

Exclusion Criteria:

• Pre-existing severe liver disease
• Pre-existing severe chronic kidney disease
• Pre-existing interstitial lung disease
• Pre-existing severe COPD or other structural lung disease
• Receiving invasive mechanical ventilation
• Currently Pregnant or Breast Feeding
• Poor baseline health conditoin
• Disability to complete lung function test
• Receiving pirfenidone wthin half-year