It is suggested in the paper that the Bragg peak of a heavy ion beam may be a useful means for investigating the site-chosen mutation. The principle and an experimental setup for measuring the Bragg Peak of heavy inn beam are described.After different materials were normalized to wheat material according to density

the Bragg peak location of 14N7+ ion beam with initial energy of about 50 MeV/u in wheat material was determined using twin ionization chambers. A depth of about 4.85mm for the peak location and a maximum range of about 5.5mm for the ion beam were finally obtained.