Abstract: To explore the influence of expansive agent content on impermeability of shrinkage-compensating concrete, focusing on the study of the impermeability of the concrete after the addition of expansive agent, the coupling influences of two factors, water-cement ratio and expansive agent content, on the impervious performance of concrete and the optimal value are discussed on the basis of the impermeability test on shrinkage-compensating concrete specimens. The research results indicate that the water-cement ratio and dosage of expansive agent affect the impermeability of shrinkage-compensating concrete, and different combinations have different effects. When the water-cement ratio is 0.45, the expansive agent will reduce the impermeability of concrete; while the water-cement ratios are 0.55 and 0.65, the concrete mixed with a certain amount of expansion agent can improve its impermeability, and their best dosages are from 6% to 8% and 11% to 12% respectively.