Abstract: Arsenic trioxide(As₂O₃)effectively triggers apoptosis in acute promyelocytic leukemia(APL)cells and induces complete remission and cure in most APL patients,if they can refrain from early mortality.In the last few years,it has been under investigation as a potential treatment for non-APL leukemia and a variety of solid tumors.In the meantime,it has been found that As₂O₃ also inhibits proliferation of non-APL leukemia cell and several solid tumor cell such as liver,esophageal,and gastric cancer cell in vitro or in vivo in the more and more studies.The molecular mechanisms that As₂O₃ induces cellular apoptosis in non APL leukemia cell and solid tumor cells have been discussed,which also includes building new targeting preparation in order to obtain much more satisfying therapeutic effect and relieve its cellular toxic and side effect and so on.Here,we give a summary which is connected with the research progress above.