Constantly in recent years, geosynthetic materials widely applied in seepage control of water conservancy projects, because of its permeability coefficient is small, the material performance is stable, light quality, low cost, fast construction, it can be used for flood control and water storage, prevent sewage into the groundwater etc. Composite geomembrane whole reservoir plate defense technology can effectively solve the problem of dam body, dam foundation, reservoir plate leakage. Composite geomembrane seepage effect is very significant, and the construction operation is relatively simple, but in the process of composite geomembrane material selection, there are many factors to consider, the specific content is as follows: It is in the aspect of material selection, the flatness of roadbed, allow scope of tensile stress, elastic modulus, laying range and other comprehensive consideration, there are also requires the expose, burying, climate, service life, etc, to satisfy the corresponding conditions of use, according to relevant regulations, set of impermeable layer thickness, This can give the basic guarantee for the improvement of construction quality