Abstract: Using the reaction between 7Li ion beam and hydrogen of wheat and the detection of 7Be, the track of 7Li ion beam in wheat is studied. The result shows that a good relationship for the track of 7Li ion beam related to the energy exists in the energy range of 22 0～ 42.3 MeV, and can be described by the equation of y = 1.207 3 + 31.877 x - 0.242 x 2 (r 2 = 0.999 5). The tracks vary in dosage from 1.28×10 10 /cm 2 to 1.28×10 12 /cm 2 as an equation of y = 265.65 + 23.886ln x (r 2 = 0.975 8).