The conversion of rangelands to other land uses generates many negative environmental side effects and increases the vulnerability of pastoralists' livelihoods. In this regard, it would be important to predict the future land use changes and to understand the pastoralists' knowledge, attitude, and behavior toward the rangelands' conservation and sustainable management. In this study, the land use changes of Iran Kishlak pastoralist settlements were initially predicted using the Markov chain model and the vulnerability of the study area was determined using the fuzzy analytic hierarchy process in terms of environmental stresses during various years. Also, to explore the rangeland conservation behaviors of pastoralists, the theory of planned behavior (TPB) was employed. The results indicated that continuation of the current trend of land use change would lead to the intensification of environmental vulnerability, as well as further reduction of rangeland, forest, and water body area. The results of estimating the TPB model revealed that the attitude, subjective norms, and perceived behavioral control could account for 75% of the variance changes in the pastoralists' intention toward rangeland conservation. Compared with the perceived behavioral control, the intention toward rangeland conservation had a stronger effect on rangeland conservation behavior. On the basis of the findings of this study, we concluded that to analyze the pastoralists' rangelands conservation behaviors, the use of TBP can be the first step toward preventing the degradation of vegetation and sustainable management rangelands. Accordingly, it is recommended that pastoralists be provided with technical and economic assistance in the field of rangeland conservation strategies. This can improve their attitude and beliefs and consequently rangeland conservation behavior.