Phase ll Study of HEC585 in Patients With IPF

Inclusion Criteria: * Volunteer to participate in this clinical study and sign the ICF before the study begins; * Aged 40-80 (including 40 and 80) ; * Female or male subjects with child-bearing potential who agree and promise to take effective contraceptive measures; * Diagnosed with IPF according to the Official ATS/ERS/JRS/ALAT Clinical Practice Guideline for IPF Diagnosis (2018); * FEV1/FVC ≥ 0.7; * FVC ≥ 45% predicted; * DLCO corrected for Haemoglobin (Hb) ≥ 30% predicted of normal; * In the opinion of the Investigator, subjects are willing and able to comply with the protocol requirements and attend the visit. Exclusion Criteria: * In the opinion of the Investigator, subjects underwent significant deterioration in IPF within one month before randomization; * Interstitial lung disease caused by other known causes; * Any bacterial, viral, parasitic or fungal infection that needs to be treated at screening; * Expected to receive lung transplantation during the study; * Expected survival is less than 6 months; * History of tumors within 5 years before screening (except for localized cancers such as basal cell carcinoma); * Moderate to severe hepatic insufficiency (Child-Pugh grade B or C, see Appendix 4); * History of unstable or worsening heart disease within 6 months before screening; * Cannot perform 6MWT or PFT; * Allergic to any component of HEC585 Tablets or pirfenidone tablets; * Participated in other clinical study and received the last dose within 3 months before screening; * Pregnant or breastfeeding; * History of smoking within 3 months before screening or are unwilling to quit smoking during the study; * Subjects often drink alcohol within 6 months before the screening (drink more than 21 units of alcohol a week), or refuse to reduce alcohol intake during the study; * History of drug abuse within 6 months before the screening; * Family or personal history of QT prolongation syndrome; * Any condition that, in the opinion of the investigator, would compromise the safety or compliance of the subject, or prevent the subject from completing the study. * TBil \> 1.5 × ULN or AST or ALT \> 2 × ULN; * CLcr \< 50 mL/min; * Human immunodeficiency virus (HIV) antibody is positive; * Uncontrolled hepatitis B virus infection or hepatitis C virus infection; * QTcF \> 480 ms. * Subjects have received any of the following treatments within 28 days before randomization: 1. Any cytotoxic drug or immunosuppressant 2. Therapeutic drugs for IPF, including but not limited to pirfenidone, nintedanib, prednisone at \> 15 mg/d or other glucocorticoids of the equivalent dose, N-acetylcysteine at \> 600 mg/d. 3. Moderate and strong inhibitor or strong inducer of CYP1A2. 4. Strong inducers or strong CYP3A4 inhibitors.