A multicentre, randomised, double-blind,4-stages phase III study enrolled 414 patients with chronic, previously treated ITP. Dosage could be adjusted (2.5~.75 mg/day) to maintain platelet counts 50~250×109/L

Inclusion Criteria:

1. Confirmed diagnosis of ITP ≥6 months;Platelets <30×109/L.
2. No evidence of other causes of thrombocytopenia.
3. Subjects who are refractory or have relapsed after at least one prior ITP therapy.
4. Previous therapy for ITP including rescue must have been completed at least 2 weeks prior to randomization.
5. Subjects treated with maintenance immunosuppressive therapy must be receiving a dose that has been stable for at least 1 month.
6. PT result no exceed normal by more than ±3s,APTT result no exceed normal by more than ±10s.
7. Signed informed consent.

Exclusion Criteria:

1. Patients with any prior history of arterial or venous thrombosis，or diagnosis as Thrombophilia.
2. Subjects diagnosed with tumor.
3. Have pre-existing cardiac disease within the last 3 months.No arrhythmia known to increase the risk of thrombolic events (e.g. atrial fibrillation), or patients with a Corrected QT interval (QTc) >450msec or QTc >480 for patients with a Bundle Branch Block.
4. Female subjects who are nursing or pregnant at screening or pre-dose on baseline.
5. Subjects who have previously received eltrombopag or any other thrombopoietin receptor agonist within 30 days .
6. Subject has consumed aspirin, aspirin-containing compounds, salicylates, anticoagulants, quinine or non-steroidal anti-inflammatories (NSAIDs) for >3 consecutive days within 2 weeks of the study start and until the end of the study.
7. Any laboratory or clinical evidence for HIV infection.Any clinical history for hepatitis C infection; chronic hepatitis B infection; or any evidence for active hepatitis at the time of subject screening.
8. ALT> 1.5 x upper limit of normal (ULN), AST> 3 x upper limit of normal (ULN)) DBLI> 1.2 x upper limit of normal (ULN),Scr> 1.2 x upper limit of normal (ULN)
9. The subject has participated in other clinical trial within the 3 months prior to randomization.