Abstract: In order to study effects of the malignant transformation of HLF cell induced by indissoluble Nickel sesquioxide.HLF cell was treated several time by Ni₂O₃ of different concentration in vitro.The identify of malignance on transformation HIF cell was carried out by the tests of ConA and semisolid agar culture.Ni₂O₃ can induce the malignant transfromation of HIF cell.The transformed cell proliferated rapidly.The transformed colonies,exhibited in extensive random orientation and the cells crossing-over.The frequency of transformation shows relation of dose-reaction in experimental concentration.The transformed cells could be agglutinated by lower concentration of ConA and could grow in semisold agear.There implied Ni₂O₃ can induce strongly malignant transformation of HLF cell.It may be carcinogenic to human.