Polished germanium Ge (100) was irradiated with 1.0-2.0 MeV Si+ at different doses from 4 x10(13) to 1X10(14) ions/cm(2) under different angles : 7 degrees, 45 degrees, and 60 degrees. The radiation damage is studied by the Rutherford backscattering/channeling technique. The experimental damage distribution is extracted from the spectrum based on the procedure by Feldman et al. The experimental damage distributions are compared with the result from the TRIM (transport of ions in matter) code. The results show that (1) it is easier to amorphize Ge than Si, and the damage in Ge (100) induced by MeV Sif depends on the dose, energy, irradiation angle, and annealing temperature also; (2) the shape of damage profile in Ge (100) induced by 2.0 MeV Si+ under 60 degrees irradiation can be described well by the TRIM prediction, except the near-surface region where the experimental damage ratio is higher than that given by the TRIM prediction; (3) after 800 degrees C annealing, damaged Ge (100) trends to be recrystallized.