Inclusion Criteria:  The patients have provided written informed consent prior to enrollment. 18-65 years old. Diagnosed as ITP secondary to connective tissue diseases (including but not limited to systemic lupus erythematosus, Sjogren's syndrome and rheumatoid arthritis), primary ITP with positive antinuclear antibody but not up to the diagnostic criteria of connective tissue diseases, primary Evans syndrome, Evans syndrome secondary to connective tissue diseases, and primary ITP with positive Coomb's test but not up to the diagnostic criteria of Evans syndrome. Platelet count<30 ×10^9/L at screening. Patients who have received at least one first-line treatment of ITP (glucocorticoid and / or intravenous immunoglobulin) in the past, failed (poor efficacy, or failure to maintain efficacy, or relapse), or had contraindications, intolerance, or refusal of first-line treatment. Treatment for ITP (including but not limited to glucocorticoids, recombinant human thrombopoietin (rTPO), and other TPO receptor agonists other than eltrombopag) must be completed before enrollment, or the dose must be stable or in a phase of reduction within 2 weeks before enrollment. Immunosuppressants (including but not limited to azathioprine, danazol, cyclosporine A, mycophenolate mofetil) must be finished before entering the group, or the dose must be stable or in the reduction period within 3 months before entering the group. Effective contraceptive measures will be taken during the clinical trial.  Exclusion Criteria:  Thrombocytopenia secondary to thyroid disease. Patients with any prior history of arterial or venous thrombosis, and with any of the following risk factors: cancer, Factor V Leiden, ATIII deficiency, and antiphospholipid syndrome. Those who had received rituximab within 6 months or who had previously failed to respond to low-dose rituximab. Patients who had failed to respond to the previous use of eltrombopag (75 mg once a day for more than 4 weeks). Patients who have received splenectomy within one year or have splenectomy plan within one year. Patients with lupus encephalopathy or lupus nephritis. Patients with cataract. Patients with infectious fever (including but not limited to pulmonary infection) within 1 month or with active infection during screening. Existing hepatitis B virus, hepatitis C virus replication or HIV infection. Patients with agranulocytosis (ANC <1× 10^9/L), or moderate and severe anemia (HGB < 90g/L). For patients with Evans syndrome, patients with HGB< 60g/L will be excluded. Severe liver dysfunction (alanine aminotransferase or glutamic oxaloacetic transaminase > 3×ULN), or bilirubin level > 2×ULN except patients with Evans syndrome. Patients with severe cardiac or pulmonary dysfunction. Severe renal damage (creatinine clearance < 50 ml/min). There were surgical planners during the study. History of psychiatric disorder. Pregnant or lactating women or those planning to be pregnant during the trial. Patients with a history of drug/alcohol abuse (within 2 years before the study). Patients that have participated in other experimental researches within one month before enrollment. Any other circumstances that the investigator considers that the patient is not suitable to participate in the trial.