To understand the trend of morphological changes in relation to the initial configuration of artificial salt marshes, we conducted an experiment in a virtual space using the numerical model Delft3D. These changes act as important variables in the propagation of vegetation which has various engineering and ecological functions as a nature-based solution. The selected forms of salt marshes are divided into three types according to the number of spacings between them, and a case without marshes has also been added. In the simulations, the scenario of external force applied to the marshes, and their surrounding space includes conditions both suitable for marsh expansion and dominated by wind. As a result of the experiment, the potential vegetation expansion area showed an increasing trend at the beginning of the experiment in all cases, gradually decreasing over time to reach a quasi-equilibrium stage. The expansion ratio tended to increase with the number of spacings in the initial shape of the marshes when the wind was not dominant. However, this difference decreased as the influence of wind became stronger. This suggests that the configuration of marshes and climate have engineering and ecological significance for the surrounding space in the design of artificial salt marshes.