Aim To investigate the effect of MTX(included(±)MTX,(+)MTX and(-)MTX)on the proliferation of ECV304 cells and to explore its mechanisms.Methods ECV304 cells were cultured.The cell proliferation was determined by MTT.The morphological changes were inspected by inverted microscope.Cell cycle phases were assayed by propidium iodide staining flow cytometry.Results ECV304 cells were treated with(+)MTX,(-)MTX and(±)MTX at 1～150 μmol·L~(-1) for 24,48,72 h.The results showed that the proliferation of ECV304 cells was significantly inhibited under different conditions.The order of the inhibited efficacy was(+)MTX>(±)MTX>(-)MTX.The morphology of ECV304 cells were changed by(+)MTX,(-)MTX and(±)MTX treatment,which included the cell shrinkage,chromatin condensation.After administration of 10 μmol·L~(-1) of(+)MTX,(-)MTX and(±)MTX for 48 h,the cell cycle phases were assayed by propidium iodide staining flow cytometry.The result showed DNA replication was interfered by(+)MTX,(-)MTX and(±)MTX treatment.Conclusions The proliferation of ECV304 cells has the chiral selective effects by(+)MTX and(-)MTX treatment,and the inhibition on ECV304 cells proliferation of(+)MTX is significantly stronger than that of (-)MTX.