Abstract: [Objective] In order to further study the effects of planned fire on the ecological stoichiometry of carbon, nitrogen and phosphorus in the roots of Pinus yunnanensis. [method] In this study, a year after the planned fire in Zhaobi mountain, Xinping County, Yuxi City, Yunnan Province, was taken as the research object. The root systems of Pinus yunnanensis in the control plot (UB) and the fire plot (PB) were collected, and the changes of living root biomass (B), morphological distribution, root organic carbon (ROC), root total nitrogen (RTN), root total phosphorus (RTP) and eco stoichiometry characteristics were analyzed. [results] ① one year after the fire, the diameter class B of Pinus yunnanensis was 7.553-288.368 g / m2, which was lower than that of UB (6.9% - 21.5%) in 0-20 cm soil layer; One year after fire, the biomass density (RBD), root length density (RLD), and root surface area density (SAD) of fine roots decreased (0.5% - 21.5%) in 0-20 cm soil layer, while the specific root length (SRL) and specific surface area (SSA) of fine roots and middle roots increased (4.1% - 21.5%) in 0-20 cm soil layer; ② One year after fire, the ROC of fine and middle roots was 335.87-492.8 g / kg, RTN was 1.934-5.724 g / kg, RTP was 0.793-1.154 g / kg, and increased in 0-10 cm soil layer (2.19% - 38.35%); The root C:N (RC:N) and root C:P (RC:P) of absorbing and transporting roots were 58.646-140.45 g / kg and 299.336-422.846 g / kg, respectively, which significantly decreased (29.57% - 39.35%) in 10-20 cm soil layer (P < 0.05); The root N:P (RN:P) of different diameter classes were less than 14, which may be limited by N; ③ Correlation analysis showed that under PB, SRL, SSA, RLD, RTN, RTP and RN:P showed extremely significant positive correlation (P < 0.001), and B, RBD, ROC, RC:P, RC:N showed extremely significant positive correlation (P < 0.001). [Conclusion] It is planned that Pinus yunnanensis will respond to the fire disturbance by cooperating with the morphological plasticity of fine roots to efficiently absorb nutrients and increasing the structural support of robust roots, and adapt to the post fire recovery environment by adjusting morphological characteristics and stoichiometry.