Quintary Zr52.5Cu17.9Ni14.6Al10Ti5 bulk amorphous alloys were synthesized with industrial sponge zirconium. The wedge-shaped samples added with Sc were prepared. The mechanism of Sc increaseing the GFA of the ahoy was analyzed by means of X-ray diffraction. SEM and Energy Spectrum Analysis. The results showed that adding Sc to the alloy could cause the transformation of phase structure and the composition of the pre-separation phase in the transitional region of the quintary alloy. Sc with great capacity of deoxidization could decrease the existence of Zirconium oxide or Zirconium/oxygen clusters in the alloy, and eliminate heterogeneous nucleants in the melt. Consequently. adding Sc to the alloy could increase the GFA of the quintary alloy.