Using Pirfenidone to treat Grade 2 or Grade3 radiation-induced lung injury, and observe the efficacy and safety of the drug.

The study is a randomized, controlled, multi-site clinical trial.

Inclusion Criteria:

1. 18-75 years old (including 18 and 75 years);
2. clinically diagnosed grade 2 or 3 radiation-induced lung injury;
3. the course of radiation-induced lung injury is less than 2 months;
4. ECOG 0-2;
5. the expected survival time is more than 6 months;
6. the functional level of major organs meets the following standards: ANC≥3.0×109/L，PLT≥100×109/L，Hb≥90g/L, TBIL、BUN and Cr≤1.5×ULN， ALT、AST≤2.0×ULN
7. capable of eating solid food upon enrollment;
8. subjects will voluntarily participate in this study and sign the informed consent.

Exclusion Criteria:

1. have a history of chronic bronchial acute attack or severe pulmonary heart disease;
2. pneumonectomy;
3. tumor progression;
4. severe pulmonary infection;
5. creatinine clearance rate < 30ml/min, severe renal disease or need dialysis;
6. concomitant with other serious diseases: for example, myocardial infarction within 6 months, uncontrolled diabetes, etc., were considered not suitable for the participants in the study;
7. patients with active peptic ulcer;
8. pregnant women and patients with mental illness;
9. participating in clinical trials of other drugs within 3 months;
10. the investigator determined that subject was not suitable.