Roads are linear human-made infrastructures which affect landscape structure and function (ecosystem services) in two phases of construction and utilization, and are one of the most important factors in landscape fragmentation and habitat degradation. Chaharmahal Bakhtiari province is one of the main Zagros forests habitats that consists of many important wetland and protected areas. In this study, the impacts of roads network on landscape structure and function in Chaharmahal and Bakhtiari during 2000 -2015 have been evaluated. For this purpose, land use maps produced using Landsat images from ETM + and OLI sensors of 2000 and 2015 respectively, and entered in Land Change Modeler (LCM) to detect land use changes during the study period. Landuse maps were analyzed with and without roads network. Impacts of road network on landscape structure was quantified using several landscape metrics including Patch Density (PD), Edge Density (ED), Mean Patch Fractal Dimension (MPFD), Mean Patch Size (MPS) and Patch Size Standard Deviation (D) in 2000 and 2015. Impacts of Road network in utilization phase have been also analyzed using Spatial Road Disturbance Index (SPROADI), as a new landscape Index. This index uses three sub-indices including traffic intensity, vicinity impact and fragmentation grade to calculate the ecological impacts of road networks. In order to estimate economic value of ecosystem services (ES), the obtained values was updated for 2000 and 2015 using global inflation rate. In addition, landscape stability was calculated using the three metrics including Aggregation Index (AI), Contagion (CONTAG) and Shannon's Evenness index (SHEI). Results indicated that during the last two decades land cover change have been occurred mainly in Zagros forest ecosystem and many of forest patches have experienced area loss and changed to range lands, agriculture and residential areas. Results obtained through quantifying the landscape Index (SPROADI) is also showed that the degree of disturbance by roads network is more than 54 which caused increasing landscape fragmentation and decreasing the landscape stability in the study area. The results of this study revealed that wide range of natural landscape and ecosystem services of Chaharmahal and Bakhtiari were negatively affected by roads network. Keywords: Road Network, Landscape Structure, Ecosystem Services, Landscape Metrics, SPROADI.