A method of evaluating characteristics of a work piece includes forming a photosensitive layer on the work piece. Then an ion implantation is performed on the work piece. The work piece is radiated, and an optical intensity of the photosensitive material on the work piece is calculated. The ion implantation pattern is evaluated according to the optical intensity. A chemical structure of the photosensitive material is changed upon the ion implantation. The work piece is recovered by reversing the chemical structure of the photosensitive material or removing the ion interrupted photosensitive material by chemicals.