Abstract: As the "corridor" in ecology landscape, roads have linear effect on ecosystem and lead to fragmentation of ecosystem. Road network, as a corridor network, places an enormous impact on the ecosystem fragmentation. In order to analyze how the road network destroys ecosystem and influences the biodiversity of ecosystem, this article imports the method from ecology landscape to the road network planning and environmental assessment, adopts the overlapping-map method in GIS, and analyzes the potential changes of ecology structure led by the road network planning. The method includes four steps, namely, drawing landscape map, classifying landscape, calculating landscape index and analyzing the impact on the road network. And the results show that this method is applicable to the quantitative analysis of the effect on ecosystem during the implementation of road network planning, thus provides some reference to ecological planning.