Si crystals were implanted with 2.0- MeV Er+ at the doses of 5×1012 ions/cm2, 1×1014 ions/cm2, 5×1014ions/cm2, 1×1015 ions/cm2 and 2.5×1015 ions/cm2. Conventional furnace thermal annealing was carried out in the temperature range from 600 °C to 1150 °C. The depth distribution of Er, associated damage profiles and annealing behavioar were investigated using the Rutherford backscattering spectrometry and channelling (RBS/C) technique. A proper convolution program was used to extract the distribution of Er from the experimental RBS spectrum. The obtained distribution parameters, projected range Rp, projected range straggling ΔRp and skewness SK were compared with those of TRIM96 calculation.The experimental Rp and SK values agree well with the simulated values, while the experimental ΔRp is larger than TRIM 96 simulated value by a factor of 18%. The damage profile of silicon crystal induced by 2.0-MeV Er+ at a dose of 1×1014 ions/cm2 was extracted using the multiple-scattering dechannelling model based on Feldman’s method, which is in a good agreement with the TRIM96 calculation. For the samples with dose of 5×1014 ions/cm2 and more, an abnormal annealing behavioar was found and a qualitative explaination has been given.