Abstract: In order to improve the soil quality and land use efficiency in the reclamation area, the dynamic difference method and niche algorithm were introduced to design and study the spatial distribution optimization method of land reclamation GIS. Firstly, using digital elevation model(DEM) data at different time points, a DEM model of land reclamation area based on dynamic difference method was constructed to reflect the topographic changes in the process of reclamation. By simulating the survival and reproduction mechanism of species in a specific niche in nature, the soil quality improvement index and vegetation restoration index were calculated, and the GIS spatial ecological optimization objective function was established. In order to realize the optimization of spatial distribution, GIS space was divided into multiple grid units using grid system, and the reclaimed land was coded. The objective function was solved under the constraint conditions, and finally the comprehensive optimization of GIS spatial distribution was realized. The experimental results showed that the land use efficiency of the reclaimed area has been significantly improved, and the soil quality has also been significantly improved.