A Randomized, Double-Blind, Placebo-Controlled, Multicenter Study of the Efficacy and Safety of Qifangfeixian Granules in the Treatment of Connective Tissue Disease-Associated Interstitial Lung Disease (CTD-ILD)

Inclusion Criteria: * 1\. Male or female aged 18-80. 2. Both conditions (1) and (2) are met or conditions (3) are met: 1. Diagnosis of CTD: CTD can be clearly diagnosed by referring to the classification criteria of each disease. SLE, SS, SSc, RA, PM/DM, etc. can be diagnosed according to the corresponding international classification standards. 2. Diagnosis of ILD: Combined with the patient's symptoms such as progressive dyspnea, dry cough, pulmonary signs such as Velcro rales in both lungs, pulmonary function examination suggesting restrictive ventilation disorder and diffusion dysfunction, High-resolution CT of the chest indicated diffuse nodules, ground-glass changes, alveolar consolidation, thickening of interlobular septum, downline pleura, mesh shadows with cyst formation or cellular changes, tractive bronchiectasis, or structural changes of the lung. 3. ILD (confirmed by high-resolution chest CT or surgical lung biopsy) is present, and ① other known etiology is excluded; ② A definite CTD cannot be diagnosed; (3) At least 2 of the following 3 characteristics: A. Clinical manifestations: (1) distal finger skin cracks (" technician hand "); (2) distal fingertip skin ulcer; (3) Inflammatory arthritis or polyjoint stiffness ≥60 min; (4) telangiectasia of the palm or finger abdomen; (5) Reynolds phenomenon; (6) unexplained swelling of the fingers; (7) Unexplained fixed rash of extended fingers (Gottron sign). B. Serological manifestations: (1) ANA titer ≥ 1:320, diffuse type, spot type, homogeneous type, or ①ANA nucleolar type (arbitrary titer), or ②ANA centromere type (arbitrary titer); (2) Rheumatoid factor ≥2 times the upper limit of normal reference value; (3) Positive anti-CCP antibody; (4) Anti-double-stranded DNA antibody is positive; (5) Anti-SSA (Ro) antibody positive; (6) Anti-SSB (La) antibody positive; (7) Positive anti-ribonucleoprotein antibody; (8) Positive anti-SM antibody; (9) Anti-topoisomerase (Scl-70) antibody was positive; (10) Anti-TRNA synthase (such as Jo-l, PL-7, PL-12; Others include EJ, 0J, KS, Zo, tRS) antibody positive; (11) Anti-PM-SCL antibody is positive; (12) Anti-melanoma differentiation related gene 5 (MDA5) antibody was positive. C. Morphological findings: (1) Chest high-resolution CT findings: ①NSIP, or ②OP, or ③NSIP overlapping OP, or ④LIP; (2) Pathological types of surgical lung biopsy: ①NSIP, or ②OP, or ③NSIP overlapping OP, or ④LIP, or ⑤ interstitial lymphocyte infiltration associated with hair center formation, or ⑥ diffuse lymphoplasmic cell infiltration (with or without lymphofollicular formation); (3) Multiple thoracic involvement (except interstitial pneumonia) : ① unexplained pleural effusion/pleural thickening; ② Unexplained pericardial effusion/pericardial thickening; (3) Endogenous airway diseases of unknown origin, including airflow obstruction, bronchiolitis, or bronchiectasis (confirmed by pulmonary function, imaging, or histopathology); ④ Pulmonary vascular disease of unknown cause. Exclusion Criteria: * 1\. When visiting 1, set AST and ALT to 1.5x ULN 2. Bilirubin \> 1.5 x ULN at visit 1 3. At visit 1, creatinine clearance was \< 30 mL/min as calculated by Cockcroft - Gault formula. 4\. Patients with underlying chronic liver disease (Child Pugh A, B, or C liver injury). 5\. Received other investigational medications within 1 month or 6 half-lives (whichever is greater) prior to the screening visit (visit 1). 6\. Significant pulmonary arterial hypertension (PAH) as defined by any of the following criteria: (1) clinical/echocardiographic evidence of prior significant right heart failure; (2) Medical history, including the right cardiac catheter showing cardiac index ≤2L/min/m2; (3) parenteral administration of eprostol/traprostacycline is required to treat PAH. 7\. Other lung abnormalities deemed clinically significant by the investigators. 8. Major extrapulmonary physical limitations (e.g., chest wall malformations, massive pleural effusion). 9\. Cardiovascular disease, any of the following: (1) severe hypertension within 6 months of visit 1, uncontrollable after treatment (≥160/100 mmHg); (2) myocardial infarction within 6 months of visit 1; (3) Unstable angina pectoris within 6 months of visit 1 10. History of severe central nervous system (CNS) events. 11. Known allergy to the experimental drug. 12. Other medical conditions that may interfere with the testing procedure or, as determined by the investigator, may interfere with trial participation or may put the patient at risk when participating in the trial. 13\. Women in this trial who are pregnant, breastfeeding or planning to become pregnant. 14\. Patients were unable to understand or follow trial procedures, including completing questionnaires on their own without assistance.