Abstract: It was indicated by numerical analysis and prototype observation that the tensile stress distributed at the left side and right side of face slab of concrete face rockfill dams was usually large and sometimes even larger than tensile strength of concrete.The face slab would crack probably if the tensile stress was larger than the tensile strength of concrete.In order to solve this complex problem,a new idea—broken line type face slab was suggested.Comparison between the stress-strain behavior of broken line type face slab and that of straight line type face slab was made by numerical analysis with three—dimensional finite element method.The calculation results showed that the tensile stress of broken line type face slab was much less than that of straight line type face slab.Moreover,its opening displacement of both the vertical joints and the perimetric joints were also smaller.Therefore,the broken line type face slab could be much safer than the straight line type face slab,especially for high dams or dams in steep-walled valley.