The abutment is the part where the by-pass seepage and contact erosion often happen to make the dam not work normally, which is the key point during design and construction, so Design Specifications for Rolled Earth-Rock Fill Dams (SL274-2001) require excavating into the slightly weathered rock mass for the core wall and the reversed filter and the abutment. The spreading gradation earth-rock fill dam with crushed-stone-earth core wall is 123m high, and the highly weathering natural depth of the phyllite and sandstone at abutments on both bank is 14.6～66.4m. According to the Specification, the excavation quantity is enormous. It is practically excavated into the highly weathering zone, which can not meet with the Specification. The treatment scheme for the highly weathering rock mass on both abutments and grouting tests and grouting technics are introduced in detail. The feasibility to adopt consolidation grouting and seepage treatment measures is argued and the treatment measures and construction control standards are proposed.