The influence of the high temperature processing on the strain stored in SiGe hetero-epilayer was studied by means of RBS/Channeling. Channeling angular scan along the ,< 110> axial direction in the (100) plane was used to characterize the tetragonal distortion in the SiGe strained layer. The strained crystal structure parameters were acquired by combining the determination of strain with the elasticity theory. It is shown that the strain stored in the SiGe epilayer has significantly change (relaxation factor from 0.023 to 0.84) after high temperature annealing. The potential strain relaxation mechanisms were discussed. The influence of the high temperature processing on the strain stored in SiGe hetero-epilayer was studied by means of RBS / Channeling. Channeling angular scan along the <110> axial direction in the (100) plane was used to characterize the tetragonal distortion in The strained crystal structure parameters were acquired by combining the determination of strain with the elasticity theory. It is shown that the strain stored in the SiGe epilayer has significantly change (relaxation factor from 0.023 to 0.84) after high temperature annealing. The potential strain contraction mechanisms were discussed.