Abstract: The geological suitability evaluation of underground space development is an important method to carry out underground space development rationally and reduce geological risks. The suitability evaluation is a typical multi-criteria comprehensive evaluation problem, and the weight plays a crucial role in the accuracy of the evaluation. Traditional evaluation methods often rely on unilateral subjective or objective weights, leading to significant limitations in accuracy. Taking Xi’an city as a case study, this paper combines the geological environmental characteristics of the research area, selects 13 evaluation indicators such as terrain slope, groundwater abundance, and rock-soil types, to establish an evaluation index system for the geological suitability of underground space development. using the AHP method to determine the subjective weights of the indicators, utilizing the CRITIC method to calculate the objective weights, integrating the two through the principle of minimum discrimination to form combination weights, and applying the comprehensive index method to evaluate the suitability of underground space development at various depths in the research area, obtaining more accurate and reasonable evaluation results. The results show that this method considers the decision-makers' preferences for evaluation factors while striving to reduce the subjectivity and arbitrariness of weighting, achieving unity between subjective and objective weighting results, thereby making the decision results authentic and reliable, and providing a more scientific basis for decision-making in underground space development and utilization.