Ni-implantation has been conducted for sputter deposited Zr alloy films to investigate compositional dependent amorphization behavior in proportion to Ni in Zr alloys. As-deposited Zr and Zr–Cu with thickness of 200 nm shows columnar hcp-Zr and nano-crystalline hcp-Zr(Cu), respectively. Implantation of 150 keV Ni⁺ with the amount of 1×10¹⁷ ions/cm² induces amorphization of Zr and Zr(Cu) with 100 nm in thick. Critical amorphization concentration of penetrated Ni decreases for Ni-implanted Zr–Cu film to be 10 at%Ni as comparison with that of 20 at%Ni for Zr film. The displacement collision effect has been examined by penetration of 300 keV-Ni⁺. As increasing the beam energy, penetration depth increases to yield equi-axed crystalline surface and inside amorphization, which corresponding to compositional gradient of penetrated Ni. This compositional dependent amorphization via ion implantation implies that induced amorphization is attributed to chemical reaction between penetrated Ni with constituents.