To know water resources and analysis of its spatiotemporal distribution in arid and semi-arid regions is of great significance for long-term water and land use planning and management. In this study, soil and water assesment tool (SWAT) model was used to predict the effects of climate change and land use on runoff and water resources components in a part of Lordegan watershed, central Iran. In order to assess the effects of land use change on runoff production and water resources three different maps including the past (1988), the current (2010), and the capability land use maps were acquired. Monthly runoff simulated by SWAT model using the current land use map (model I) was used for the calibration and validation analysis using SUFI-2 algorithm. Then the optimized parameters obtained from the calibration analysis were entered into the Model II (constructed model using the land capability map) and Model III (constructed model using the past land use map) in the environment of SWAT-CUP software. To investigate climate change in near future (2011- 2039), intermediate future (2040- 2069), and far future (2070- 2099) we used the future climate projections from HadCM3 under A2 emission scenario that have been downscaled based on the observed data of CRU dataset, and CO 2 concentration predicted based on the A2 scenario emission. Percentage of changes in precipitation and average monthly temperature data were calculated and fed into the existing SWAT hydrological models (models I and II). In results, the obtained values ??of both R 2 and NS in calibration were 0.83 and r-factor and p-factor values were 1.06 and 0.49, respectively. For the validation step, the R 2 and NS ??coefficients were 0.75 and 0.74, respectively. The values of these coefficients were 0.74 and 0.73 for the Model II and 0.71 and 0.71, for the Model III, respectively. The percentage changes in future precipitation for different months of the year varied from -5/38 to 287% such that the greatest decreases in precipitation occurred in June in the far future. The highest obtained increases were simulated for the warm season of the year in September in the intermediate future. The average monthly temperature in all three periods was increased except during the month of February in the near future. This increase was from 0.65% in April for the near future to 6.2% in August for the far future. Land use change had significant effect on both base and peak flows. Such that for the past period (1996- 2011), the minimum base flow and maximum peak flow were encountered for the Model I. However, the impact of climate change on runoff was greater than the land use change. Such that the values of changes in peak flow and base flow in both investigated models (constructed using current land use map and land capabilities map) in all three periods were greater than that for the past period. Overall the changes for the first model was greater than the second model. The simulated blue water and green water resources were affected by land use change and distribution of the precipitation in the study area. So that the lowest precipitation was simulated for the central and northern areas of the study area. The least amounts of the blue water and green water (green water flow/storage) were obtained for these areas. Likewise, the southern parts with the highest precipitation proportion had the highest amount of water resources. In the future periods like the intermediate and far future the components were affected by climate changes and the land. In all scenarios, the results were negative for all components of water resources in the first model and values of water resources had drastic changes, indicating a more critical situation. Moreover, the situation was better for the second model, such that water resources components had either increasing or decreasing trend. Overall, the negative impacts of climate change on water resources in the Model I was stronger than the model II. Key words: SWAT model, SUFI-2 algorithm, Blue water, Green water, Climate change, Land use, Runoff