目的：阐明氧化砷治疗急性早幼粒细胞白血病（ＡＰＬ）的机制。方法：以原代ＡＰＬ细胞为模型，将不同浓度的氧化砷作用于ＡＰＬ细胞，并对其作用机制进行研究。结果：高浓度氧化砷选择性诱导ＡＰＬ细胞凋亡，低浓度氧化砷诱导新鲜ＡＰＬ细胞部分分化。进一步研究发现，不同浓度的氧化砷均能快速调变和降解ＰＭＬ－ＲＡＲα蛋白。结论：氧化砷对ＡＰＬ细胞存在双重效应，即诱导凋亡和部分分化。 Objective: To elucidate the mechanism of arsenic trioxide in the treatment of acute promyelocytic leukemia (APL). Methods: The primary APL cells were used as a model to treat different concentrations of arsenic oxide on APL cells, and the mechanism of action was studied. RESULTS: High concentrations of arsenic selectively induced apoptosis of APL cells, and low concentration of arsenic induced partial differentiation of fresh APL cells. Further study found that different concentrations of arsenic oxide can rapidly modulate and degrade PML-RARα protein. CONCLUSIONS: As2O3 has dual effects on APL cells, namely induction of apoptosis and partial differentiation.