In order to analyze the effect of different types of injected water on reservoir seepage ability，core samples in H oilfield of Middle East was prepared to simulate formation water and injected water seepage experiments of single phase and oil-water two phase were made. The experiment results were comparatively analyzed and described by mathematical model. The results show that：the scouring effect of injected water A results in loss of solid particles and mineral compositions from core samples，which leads to stronger seepage ability of the core samples. So oil absolute permeability，water absolute permeability and the sum of oil and water absolute permeability are increased. The lipophilicity of the core samples is weakened and the hydrophilicity is enhanced. The residual oil saturation is reduced and the equivalent permeability point shifts to the right. Compared with the result of simulated formation water displacement，the oil displacement efficiency is increased by 2% to 5%. Mathematical model based on the experimental results can give more accurate description on oilwater seepage rule in early，middle and late stages of oilfield exploitation.