Many amorphous alloys have been developed to date, but the low plasticity has limited their application. To achieve an amorphous alloy with high plasticity, a series of (Ti₄₀Zr₂₅Cu₉Ni₈Be₁₈)_100-xTM_x (x=0, 1, 2, 3, 4 at.%, TM=Nb, Y) alloys were designed to study the influence of Nb and Y addition on the plasticity. The amorphous samples were prepared using the vacuum melting and copper mold casting process. The microstructures, glass forming ability and mechanical properties of the alloys were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), depth-sensitive nanoindentation, and uniaxial compressive test. The plasticity of different bulk amorphous alloys was investigated by measuring the plastic deformation energy (PDE) during loading. The relationship between the PDE value and plasticity in bulk amorphous alloys was explored. Results show that Nb addition decreases the PDE value and promotes the generation of multiple shear bands, which significantly increases the fracture strength and plasticity, while the addition of Y element reduces the fracture strength and plastic strain of the alloy.