[Objective] The impact of forest fire disturbance on soil nutrients and ecological stoichiometric characteristics of Pinus yunnanensis forest was investigated in order to provide data support for soil nutrient management and vegetation restoration in regional burned areas. [Methods] This study was conducted in the Hongtashan Nature Reserve， Yuxi City， Yunnan Province， with P. yunnanensis as the study species. A combination of field experiments and laboratory analysis was applied to examine physicochemical properties and ecological stoichiometric ratios of carbon， nitrogen， and phosphorus in the 0—40 cm soil layer under different fire intensities （unburned， light burning， medium burning， and severe burning）. Difference and correlation analyses were performed. [Results] ① For different fire intensities， the soil bulk density， soil water content， and total soil porosity in the 0—40 cm layer were from 1.21 to 1.34 g/cm³， 3.82% to 5.71%， and 50.60% to 58.92%， respectively. Soil bulk density gradually increased with increasing fire intensity， while soil water content and soil total porosity decreased correspondingly. ② Fire disturbance significantly affected soil organic carbon （SOC）， total nitrogen （TN）， total phosphorus （TP）， and available nitrogen （AN） in P. yunnanensis forest （p<0.05）， but did not significantly affect soil pH value （p>0.05）. Compared to unburned plots， average soil SOC and TN contents decreased by 6.22%—19.56% and 17.86%—39.29%， respectively， while TP and AN increased by 2.82%—40.85% and 22.07%—173.28%， respectively， under different fire intensities. ③ Fire disturbance significantly affected the C/N， C/P and N/P ratios in P. yunnanensis forest （p<0.05）. Compared to unburned plots， the average soil C/N ratio increased by 14.05%—31.24%， and the average soil C/P and N/P ratios decreased by 48.70%—75.82% and 57.81%—84.32%， respectively， under different fire intensities. ④ Soil C/N was extremely significantly positively correlated with SOC， and extremely significantly or significantly positively correlated with total soil porosity （STP）. Soil N/P was extremely significantly or significantly negatively correlated with soil TP. [Conclusion] Fire disturbance alters soil physicochemical properties， with effects particularly significant under severe fire disturbance.