In this work, the Cu46Zr42-xAl7Y5Nbx alloys with different Nb contents were prepared by water-cooled copper mold casting. The effects of Nb addition on the structural and mechanical properties were studied. It was found that the structure remains in amorphous state at low Nb concentration (x =1, 2). However, some crystalline phases appear in the high Nb content alloy (x > 2), showing a composite structure, that is, the second phase particles dispersed in an amorphous matrix. The effects of Nb on the glass-forming ability of Cu46Zr42Al7Y5 were studied by differential scanning calorimetric (DSC). The compressive mechanical properties of Cu46Zr42-xAl7Y5Nbx alloys were studied. It was found that the compressive strength can be improved by introducing Nb. However, the ductile of the alloys were not improved by the introduction of Nb.