Rangelands are highly degraded in many climatic regions of our country, Iran, due to mismanagement and unfavorable environmental condition such as prolonged and frequent droughts, hence structural and functionality of these vital ecosystems are degraded. Functionality of rangeland landscape determines the ability of ecosystem to conserve or lose vital resources such as water, soil and organic matter. Therefore, the functionality of rangeland landscape is highly related to rangeland condition. Monitoring the rangeland condition can assist managers to identify structural and functional changes over time. Filed assessments are costly and time-consuming due to the broad scale of rangelands and also the subjectivity of the analyses. Remote sensing techniques provide a tool that can handle these problems. It is also possible to study the functionality of rangeland over a large area using some remote sensing based techniques. Functionality of rangelands can be determined using filed methods such as “Landscape Function Analysis” or remote sensing techniques such as “Cover Directed Leakiness Index (CDLI) and Leakiness Index (LI)”. This study aimed to evaluate the applicability of remote sensing-based approaches for assessing and monitoring the functionality of Isfahan's arid and semi-arid rangeland, Iran. Three locations were selected in different climatic zone in Isfahan province (two sites in arid zone including Soh and Varzaneh region and one site in semi-arid zone in Booin-Miandasht region) and TM and ETM + images in 1989, 2009 and 1999 were collected and preprocessing techniques were applied. In the next step, PD54 vegetation index of these images were calculated based on ground vegetation cover percentage and then CDLI LI indices were measured accordingly. These indices varies from 0 to 1 where zero is fully functional and one is fully dysfunctional. The calculated Cover Directional Leakiness Index for Soh(derived from 2009 TM image) and Varzaneh (derived from 1999 ETM+ image) was about 0.79 and 0.53 respectively which indicated that Soh has low functionality as its low plant cover percentage cannot capture and conserve resources but the functionality of Haloxylon plantation area in Varzanh was moderate. The other funtionality index, LI, was calculated for all 16 sub-basins of Booin-Miandasht region. Multiple sources of data such as DEM, PD54 index, dominated vegetation life forms were used to calculate LI index in LI v.4 software. The calculated LI for whole area was about 0.08 which indicated that this area has high functionality as its high plant cover percentage can capture and conserve resources. The PD54 vegetation cover percentages of all sub-basin areas were compared by filed data and their correlations were significant (P 05).The correlation between LI values and vegetation cover and bare soil percentage obtained from PD54 index was also significant (P 01). For monitoring purposes, two TM images in year 1989 and 2009 were used to detect changes in land use and functionality (LI) of Booin-Miandasht region. Change detection results revealed that the size of rangeland and agricultural lands were changed over this 20 years period. Rangeland land use was reduced from 46.84 to 42 hectar and agricultural area was increased from 2.65 to 7.39 hectar. According to results, increased cultivated lands and negative trends of rangelands leads to decrease the functionality of the whole area and increase the LI values. The functionality, LI values, of Booin-Miandasht' study area varied significantly (P 01) over this time period. In conclusion, It can be said that rangeland landscape function can be determined using remote sensing structural indices and they are very useful and effective tools and can supplement field-based assessment and monitoring in broad arid and semi-arid rangelands Key Words : Rangeland, Function, Runoff, Remote Sensing, CDLI, LI, PD54, Monitoring.