Comprehensive thinking constitutes an essential component of the core competencies in senior high school geography, and its scientifi c assessment plays a pivotal role in instructional diagnosis and item design optimization. Grounded in the Senior High Schoo Geography Curriculum Standards (2017 Edition, Revised in 2020) and integrated with the SOLO taxonomy, this study developed the Comprehensive Thinking Assessment Framework, which comprises 16 sub-dimensions. Additionally, the Situation Complexity Index and the adjustment coeffi cient K were introduced to account for discrepancies between cognitive demands and empirically observed item diffi culty. Through an empirical analysis of nine sub-items across three sets of questions from the Geography Paper II of a city-level senior high school fi nal examination in 2025, the scientifi c validity and operational feasibility of the proposed assessment system were verifi ed. The fi ndings reveal that students exhibit pervasive weaknesses in spatial causal reasoning, systemic integration and causal analysis, and critical and innovative thinking, with pronounced disparities in higher-order thinking performance. A signifi cant amplifi cation eff ect of situational complexity on item difficulty was observed, corroborated by a positive correlation between SCI and K. The difficulty prediction model, constructed on the basis of a double exponential function, yielded a mean absolute error of 0.12, indicating a satisfactory level of predictive accuracy. Consequently, the outcomes of this research can off er both theoretical underpinnings and practical tools for instructional diagnosis and item design optimization of comprehensive thinking.