Pd77.5Cu6Si16.5(at.%)bulk metallic glass with a diameter up to 11 mm was successfully fabricated by water quenching method together with melt purification.By using x-ray diffraction and transmission electron microscopy techniques,the structure of the as-prepared sample is confirmed to be glassy.The resulted sample with11 mm diameter indicates that the melt purification by fluxing method can effectively enhance the glass forming ability of Pd-Cu-Si alloy,and increase its critical size of glassy sample.