Abstract: Based on the construction interfaces in RCCD, the methods were proposed to calculate the influence thickness of construction interfaces and the corresponding physical mechanics parameters. The principle on establishing the coupling model of seepage-field and stress-field for RCCD was presented. A 3-D FEM program was developed. Study shows that such parameters as the thickness of construction interfaces, the elastic ratio and the Poisson's ratio obtained by tests and theoretical analysis are more reasonable, the coupling model of seepage-field and stress-field for RCCD may indicate the coupling effect between the two fields scientifically, and the developed 3-D FEM program can reflect the effect of the construction interfaces more adequately. According to the study, many scientific opinions are given both to analyze the influence of the construction interfaces to the dam's characteristicinteraction between the stress-field and the seepage-field.