Ar ion implantation induced superconductivity change and structural change in YBa2Cu3O7-x epitaxial films have been studied. After implantation, not only Jc and Tc of the sa-mples decreased with the increasing of Ar ion fluence, but also a metal-to-semiconducfor transition occurred. The TEM photographs showed that the lattice frame of the implanted sa-mples was nearly unchanged under low fluence. Only at high fluence, the structure was comple-tely destroyed. According to the experimental results, we suggest that the degradation of Jc and Tc may mainly result from the disordering of oxygen sublattice.