This paper discussed the effect of Suizhong 36-1 oilfield reinjection sewage on core permeability in different suspending particle sizes, different concentration of suspended substances and different injection volume of water. The experimental results showed that: The larger the suspended particles diameter, the greater the concentration, the higher the injury rate; The lower the formation permeability, the greater the damage; The core permeability was markedly decreased with the increase of the volume of injected water; The formation damage degree was D11 > mixed injection > well water.