The binary TixCu100-x（x=50

57）alloys with 40μm in thickness and 2mm in width were prepared by melt spinning method.The amorphous structure of these ribbons was observed by XRD.The thermal stabilities of Ti50Cu50 and Ti57Cu43amorphous alloys were analyzed by DSC.And the microstructures of two ingot were investigated by SEM（scanning electron microscopy）.The results show that ignored glass transition temperature Tgis observed

while only 1Kdifference is observed between crystalline temperature Txeven if the initial melting temperature Tm difference is as high as 35 Kfor Ti50Cu50and Ti57Cu43 amorphous alloys.Ti2 Cu phase in the Ti57Cu43 alloy is precipitated in the non-equilibrium solidification process by microstructures observation

leading to increasing in the required critical cooling rate of Ti57Cu43 amorphous alloy.The glass-forming ability of Ti57Cu43 alloy is reduced compared with Ti50Cu50 alloy.The relationship is discussed between competing phases of microstructures and thermal stabilities of the two amorphous alloys.