Mixed-species plantations have gradually become an effective approach for enhancing ecosystem functions in forestry production practice. However, how tree species mixture affects microbial resource limitation represented by soil extracellular enzyme stoichiometry (EES) remains poorly understood. In this study, we selected the conifer (Pinus massoniana)-broadleaf (Castanopsis hystrix) mixed forests and their corresponding pure plantations and determined the bulk soil and rhizosphere soil physicochemical properties. We also analyzed the extracellular enzyme activities (EEAs) related to carbon (C), nitrogen (N) and phosphorus (P) acquisition in the rhizosphere and bulk soil samples, then calculated the enzyme stoichiometric ratios. The objective was to assess the impact of tree species mixing on soil nutrients, microbial resource limitation, and the underlying mechanisms. The results showed that tree species mixing significantly enhanced soil nutrient status, with even-aged mixing outperforming uneven-aged mixing in terms of nutrient enrichment. The SOM content was found to be 33% (bulk soil) and 64% (rhizosphere soil) higher than that of the uneven-aged mixture in the case of the even-aged mixture. The content of TP was found to be 17% (bulk soil) and 30% (rhizosphere soil) higher, and the NH⁺₄-N was 65% (bulk soil) and 102% (rhizosphere soil) higher, in the even-aged mixture than in the uneven-aged mixture. The intensity of C limitation was significantly higher in the bulk soils of mixed forests than in the pure forests. The degree of C limitation was considerably lower in the rhizosphere soils of mixed forests than in pure forests. Soil microorganisms generally exhibited strong P limitation across all stand types. Soil pH, organic matter, and nitrogen and phosphorus nutrient content were key factors driving changes in enzyme activity and influencing microbial resource limitation. In summary, the mixture of broadleaf species with coniferous species can improve soil nutrient status and alleviate C and P limitations in soil microbial growth and metabolism. These findings have important implications for the application of mixed conifer and broadleaf plantations to ameliorate soil microbial resource limitations.