Abstract: Dynamic analysis of infinite saturated foundation is required to study the saturated soil-structure interaction. If infinite saturated foundation is simulated by a finite region, wave reflection will take place on the artificial intercepted boundary. Adopting remote artificial boundaries, this problem is solved by gradual enlargement mesh. The method is verified through an example. With gradual enlargement mesh method, not only the difficulty of implementation on other artificial boundary can be avoided, but also some uncertain factors in other artificial boundary such as boundary stability and large angle incidence and so on can be avoided, so it can be used to check other artificial boundary.