When using the temporary section of retaining dike for flood protection during the face rockfill dam construction, lacking of concrete panel construction in upstream will lead to a saturation state of most area on temporary section and dam foundation material, which would affect the stability of dam slope when the dam is completed. To study the effect of temporary section of retainins dike for flood protection on stability of CFRD, combining with the Hongjiadu concrete face rock-fill dam project, the paper analyzed the seepage under temporary section of retaining dike for flood protection by finite element method, and studied the dam slope stability in the two situations that whether temporary section retains flood or not by using nonlinear finite element method. The result showed that the impact of using temporary section for flood protection on the upstream dam slope stability against sliding will be more than the impact of that on downstream dam slope, while the impact was limited.