Mechanical properties of (Cu₅₀Zr₄₃Al₇)_100-xNb_x (x=0,1,3,6,9) bulk metallic glasses rods with a diameter of 2.5∼mm prepared by suction casting method were studied. The results of uniaxial compression tests at room temperture show that the best mechanical properties of 2.8% and 1.98 GPa for plastic strain and fracture strength, respectively, in the sample with x=3. Microstructure, fracture surface and shear bands of the samples were observed by SEM and XRD methods.