Objective:To study the clinical effects of “Bushen Jianpi Zhixue Decoction” in the prevention of thrombocytopenia after demethylation of myelodysplastic syndrome. MethodsThirty-nine subjects were randomized into two groups:control group in which 18 cases were treated with Decitabine Injection, and treatment group in which 21 cases were treated with Decitabine Injection and “Bushen Jianpi Zhixue Decoction”. After 15 days, the bleeding condition, platelet indexes and the contents of serum IL-11 were observed in both groups.  Results:①The bleeding rate was 42.86% in the treatment group and 66.67% in the control group, with lower rate in the treatment group than in the control group(P<0.05). ②After treatment, the blood platelet count(PLT), plateletcrit(PTC) and platelet volume distribution width(PDW) were increased (P<0.05) and the platelet volume(MPV) reduced(P<0.05) in both groups; there were significant differences in PLT and PDW between the two groups(P<0.05). ③The contents of serum IL-11 were of no difference between before and after treatment in the two groups and between the two groups(P>0.05).  Conclusion:“Bushen Jianpi Zhixue Decoction” can prevent thrombocytopenia after demethylation of myelodysplastic syndrome and reduce hemorrhage.