Abstract: The spatial distribution of key chemical elements in soil is a crucial foundation for tobacco cultivation planning. This study is based on 883 topsoil samples (0−20 cm) collected in 2016 from 65 typical tobacco-growing townships in Yuxi City. Seven factors were selected for analysis: organic matter, pH, hydrolyzable nitrogen, available phosphorus, available potassium, available boron, and water-soluble chlorine. First, fuzzy mathematics was employed to quantify the membership degree of each factor, and the analytic hierarchy process (AHP) was used to determine the weight of each factor. The soil fertility index (SFI) for each sample point was then calculated through weighted summation. Finally, ordinary Kriging interpolation was applied to generate a spatial distribution map of SFI across the city, enabling an evaluation of the suitability of tobacco-growing soils in Yuxi. The results show that the key chemical elements influencing soil suitability, in order of importance, are water-soluble chlorine, hydrolyzable nitrogen, available potassium, organic matter, pH, available phosphorus, and available boron. Soil suitability across the city is categorized into three levels: excellent, good, and fair. Soils rated as excellent are primarily distributed in the eastern regions of Huaning and Chengjiang, the Central Hongta District, the Western Xinping County, and the Northern Yimen County, while fair soils are mainly found in the Northern and South-central regions. Among the 65 tobacco-growing townships, 17 have soils rated as excellent, 31 as good, 14 as fair, and 3 as medium. The findings of this study provide a valuable reference for the scientific planning of tobacco cultivation in Yuxi City based on the suitability of key chemical elements in the soil.