ObjectiveTo observe the effect of Decitabine in the treatment of myelodysplastic syndrome(MDS)patients with or without DNMT3A gene mutation.MethodsFrom January 2013 to June 2017,20 MDS patients with DNMT3A gene mutation receivedtreatment in our hospital were selected as the research group.Meanwhile,20 MDS patients without DNMT3A gene mutation was selected as the control group.All patients were treated with Decitabine,and the improvement of the two groups of patients after receiving capecitabine treatment was observed.ResultsThe total clinical effectiveness rate was 65%in the research group,which was significantly higher than that in the control group(35%),with significant difference(P＜0.05).Before treatment,DNMT3A gene expression in the research group was greatly higher than that in the control group(P＜0.05),and the expression of DNMT3A after treatment was markedly decreased(P＜0.05).There was no significant difference in the incidence rate of adverse drug reactions between the two groups(P＞0.05).ConclusionDecitabine in the treatment of MDS with DNMT3A gene mutation can obtain a great effect.For MDS patients with DNMT3A gene mutation,Decitabine is a preferred choice for the treatment.