Plasma cell leukemia (PCL) is a plasma cell proliferative disorder with strong invasiveness, rapid progression and poor prognosis. The incidence of PCL is about (0.04-0.05)/100 000 per year. According to the multiple myeloma (MM) history, PCL can be divided into primary plasma cell leukemia (PPCL) and secondary plasma cell leukemia (SPCL). PPCL accounts for about 60% of PCL, and it is in the stage of leukemia at diagnosis and has no history of MM. SPCL accounts for the remaining 40% of PCL, and mostly shows as the MM end-stage manifestation, but also can be secondary to Waldenstrom macroglobulinemia, B-cell lymphoma, chronic lymphoblastic leukemia, amyloidosis, etc. Patients who progress from MM to SPCL account for 2%-4% of all MM patients. Due to the low incidence and strong clinical heterogeneity of PCL, the evidence-based medicine about PCL is relatively lacking, this article reviews the clinical characteristics of PCL and progress in its diagnosis and treatment.