Abstract: The roller compacted concrete gravity damat Silin hydro power station is of 117 mhigh. The key technological problem is the seepage path at the dam body and foundation. Two- dimensional finite element model was applied to analyse the seepage of dam and dam foundation. In calculation, it assumed that the interlayer seepage was anisotropic. According to construction method of roller compacted concrete gravity dam, three calculation schemes were adopted to research on the characteristic of seepage and other influencing factors. By seepage analysis, conclusion was gotten that the seepage characteristic of roller compacted concrete damwere determined by the seepage characteristics of layer, upstreamanti- seepage faceplate panel and seepage proof curtain.