Inclusion Criteria:  Male or female, aged between 18-60 years; PLT has not been reconstructed 14 days after Allo-HSCT (PLT reconstruction was defined as the status of peripheral PLT count > 20*109/L for consecutive 7 days without the need for PLT transfusion); Expected survival time > 3 months; ECOG performance status 0-2; Agree to receive the treatment of avatrombopag after Allo-HSCT and must sign the informed consent form.  Exclusion Criteria:  Pregnant or lactating; With severe and uncontrollable infection; With graft-versus-host disease (GVHD) with steroid resistance; With thrombotic microangiopathy; With active thromboembolism requiring anticoagulation With detected disease recurrence due to chimerism by flow cytometry; With chronic active hepatitis B and C virus infection; With secondary or multiple transplantation, or multiple organ transplantation; With severe heart disease, lung disease, diabetes and metabolic diseases; HIV positive; With a history of PLT dysfunction or bleeding disorders With the active hepatic venous occlusion disease, or a history of clinically significant hepatic venous occlusion disease (The disease was defined as the abnormal condition of painful hepatomegaly after transplantation with bilirubin ≥ 6.0 mg/dL); With progressive solid tumor; With severe bleeding requiring transfusion of more than 2 units of red blood cells, or sudden drop of blood cell volume ≥10% within 7 days prior to screening; With any other clinical trial of investigational product or device within 30 days prior to the baseline visit, except for observational study; With treatment of thrombopoietin receptor agonist (TPO-RA) one month before enrollment; Deemed unsuitable for enrollment by the investigator.