Tourism will bring certain negative impacts on environment,which are usually con-cen trated around the places for sightseeings.The spatial pattern of the itinerary system can regu-late and restrict the behavior of the visitors,and can therefore decide to a great extent the de-gree of the touring environmental impact caused by visitors.The study showed that the existing indicators from landscape ecology cannot assess the impacts efficiently since those indicators in landscape ecology usually separate the trails' spatial structure and their ecological functions in-stead of integrating them.This paper takes the Jiuzhaigou National Nature Reserve as a case study area,and pro poses a new indicator named Network Efficiency,which links the corridors' spatial pattern and their ecological functions.Compared with the traditional indicators Connectiv-ityγand Annularityα,the study shows that the Network Efficiency is more efficiently used for environmental impact assessment of the scenic spots.Besides used for environmental impact as-sessment,the Network Efficiency can also be used directly in the analysis of the itinerary capac-ity and practical use by visitors,and thus offer valuable information for tourism management .