Abstract: The geological problems of the building of Mopanshan reservoir is the seepage of the dam base and its stability of infiltration, which will influence the exertion of the engineering benefit and the safely run of the dam and it needs proper measure to control the infiltration. Through the analysis on the granule constitute of the formation of the dam base, the type of the infiltration damage apt to happen has been defined and the antiinfiltration and the permissible depression ratio has also been determined. With the Visual MODFLOW,the three-dimension numerical modeling has been carried out to analyze the see-page field of the reservoir. After the statistics analysis of the seepage factors of the field under 18 different measures and its effect, the seepage-control measure of the Mopanshan reservoir in the city of Harbin is determined that the length of left bank to control the seepage should be 200 m, purdah grouting standard 5 Lu should be the principal measure, according to the permissible depression ratio of the dam base, on the base of safety, economy, principles with reason.

Key words: dam base, three-dimensional seepage flow, seepage stability, design on seepage control schemes