In hydraulic and civil engineering, gradually actual seepage analyses exceed the upper limit of Darcy's law. More and more problems should be considered on the influence of non-Darcy flow. The mechanism and numerical solution of non-Darcian flow were discussed in this paper. Then, the Forchheimei's non-Darcy flow was regarded as the research object to establish calculation model of dam. The high ordered item was studied for the influence of non-Darcy flow analysis. The law of Forchheimei's non-Darcian flow based on the variation of parameter b was discussed and summarized. The importance of non-Darcian flow analysis and the further research direction were proposed.