Abstract: Cytometry by time-of-flight (CyTOF) is an innovative single-cell analysis technique combining with mass spectrometry principles and flow cytometry. In recent years, CyTOF has been widely used in the study of leukemia treatment for its advantages of multi-parameter, high-throughput, compensation without calculation and diversified data analysis. It can accurately determine intracellular element contents and analyze the changes of unique phenotype and complex signaling pathways of leukemia cells at the single-cell level, to study the mechanism of action of anti-leukemia drugs, discover the potential therapeutic targets of leukemia, assess the therapeutic response and deeply understand the mechanism of leukemia relapse and drug resistance. This article reviews the research progress of CyTOF principle, characteristics, advantages and its application in leukemia treatment.