The monitoring and assessment of land use/land cover (LULC) changes are critical issues in sustainable land management. The aim of the study was to assess LULC changes in the watershed using landscape metrics. The study utilized remote sensing and FRAGSTAT to analyze satellite imagery and landscape metrics from 1991 to 2021. Eight metrics were employed to quantify changes in the landscape structure and identify areas of potential degradation. The study applied the VIKOR method for vulnerability priority assessment, emphasizing the importance of considering multiple landscape metrics in the evaluation. The study highlighted the significance of each metric and its impact on land use sustainability, employing a weighted approach. The results indicated significant changes in the LULC of the Kashkan watershed over the 30-year period. The primary changes included a decrease in forest cover (18.35%) and an increase in rangeland (20.85%). Landscape metrics revealed that these changes resulted in decreased landscape connectivity and increased fragmentation. The vulnerability assessment showed that forests and rangelands have the highest and lowest vulnerability, respectively, with values of 0.997 and 0.074. The study underscores the importance of monitoring and assessing LULC changes for sustainable land management. The landscape metrics used in this study provide a useful tool for quantifying changes in landscape structure and identifying areas of potential degradation. This information can be utilized by land managers and policymakers to develop effective strategies for sustainable land management.