Abstract: The connection between core wall of dam body and anti-seepage wall of dam foundation is very important for high earth dams of 200 m level. With the development of high dam construction on deep overburden, more and more galleries are used to connect anti-seepage wall and clay core wall. We summarized the structural design problems such as the layout of gallery and anti-seepage wall, the connection between gallery and anti-seepage wall, the gallery joint layout, the anti-seepage solution at the connection of gallery and anti-seepage wall, core wall. The research results showed that the major wall gallery and the auxiliary wall insertion should be adopted in the layout of two anti-seepage walls; the inverted trapezoidal rigid joint was more suitable for the connection between the gallery and anti-seepage wall, and the structural joint between gallery and flat tunnel on both sides should be buried into the bedrock at a certain distance; high plastic clay area should be set around the gallery or the anti-seepage wall, and geomembrane should be laid at the main anti-seepage wall gallery and at the connection of the auxiliary anti-seepage wall and the core wall, and filter layer protection should be set at the downstream side.