Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematopoietic malignancy mainly affecting elderly patients. It is highly responsive to chemotherapy, but the median event-free survival is very short and has a high rate of relapse even after performing allogeneic stem cell transplantation; thus, the discovery of novel agents for the treatment of BPDCN is urgent. Chidamide is a new oral isotype-selective histone deacetylase inhibitor (HDACi). It is proved to exert a well-characterized anticancer property in a wide range of hematological malignancies, especially lymphoma. Here, we report a 41-year-old man who used oral chidamide 30 mg twice per week for maintenance therapy after receiving complete remission. For the first time in this field, we had explored the efficiency of chidamide in the treatment of BPDCN and tried to give more choices to the therapy of this disease.