Damage of speed sensitivity during water injection process exists in the Xinganling Group because of the high clay content and loose stratigraphic framework.According to the speed sensitivity experiment and the production parameters,this paper has calculated the damage radiuses and the optimal acidizing radiuses of conventional injection well and fractured injection well through theoretical derivation.This technology has been applied on 7 wells in field test.Speed sensitivity experiment shows that Xinganling Group shows m-strong to strong speed sensitivity.The damage radiuses of Ⅰ～Ⅳ layers of conventional injection well are 2.42m,0.94m,1.30m and 0.26m respectively,damage of fractured injection well is only exist in I layer and the damage radius is 3.3m.Theoretical derivation shows that the optimal acidizing radiuses of Ⅰ～Ⅳ layers of conventional injection well and I layer of fractured injection well are 2.4m,1.6m,1.6m, 1.8m and 3.3m respectively.Field test in 7 wells has confirmed that this method has strong practical applicability and can be used to the acidizing design of other sandstone oilfield.