The filtration pressure of concrete dams has the effect on the stability against sliding and the Stresses of the dams. The filtration pressure at the base of dam along the contact plane of concrete dam and rock surface and the filtration pressure in the dam are treated separately. In each case, two factors are considered: (a) the intensity of the filtration pressure, and (b) the percentage of the area over which is effective. In the past, many investigators have studied the filtration pressure at the base of dam, the results from direct measurements of existing dams are especially valuable. It is found that the present design practices are rather conservative. Method of computing the filtration pressure at the base of dam is recommended based on the theoretical analysis and the actual measurements. The filtration pressure in the dam was scantily studied. Where there are vertical drains, the customary assumption of linear distribution of filtration pressure in the dam is not satisfactory. It is recommended to treat this as a problem of filtration with free saturation surface. It is suggested to use Romanof’s formula to approximately compute the average line of saturation in the dam. In computing the stresses in the dam, it is shown that the filtration pressure should be considered as internal buoyancy force instead of external force as assumed in the present design practice. Finally, several means are proposed to relieve the filtration pressure of concrete gravity dams. The filtration pressure of concrete dams has the effect on the stability against sliding and the Stresses of the dams. The filtration pressure at the base of dam along the contact plane of concrete dam and rock surface and the filtration pressure in the dam are treated separately. In the past, many factors are studied. (A) the intensity of the filtration pressure, and (b) the percentage of the area over which is effective. In the past, many investigators have studied the filtration pressure at the base of dam, the results from direct measurements of existing dams are particularly valuable. It is found that the present design practices are rather conservative. Method of computing the filtration pressure at the base of dam is recommended based on the theoretical analysis and the actual measurements. The filtration pressure in the dam was scantily studied. Where there are vertical drains, the customary assumption of linear distribution of filtration pressure in the dam is not satisfac It is recommended to treat this as a problem of filtration with free saturated surface. It is suggested to use Romanof’s formula to approximately compute the average line of saturation in the dam. In computing the stresses in the dam, it is shown that the filtration pressure should be considered as internal buoyancy force instead of external force as considered in the present design practice. Finally, several means are proposed to relieve the filtration pressure of concrete gravity dams.