Abstract: Styrax zhejiangensis is a protected plant species with an extremely small population endemic to Zhejiang Province. The study on the contents of carbon (C), nitrogen (N), phosphorus (P), potassium (K) and their stoichiometric ratios in the root zone soil of S. zhejiangensis and its associated plants is helpful to provide a scientific basis for the forest soil management in the conservation of this species. The soil samples were collected from the 0-20 cm soil layer around the roots of nine standard plant individuals, including S. zhejiangensis, and synergistic plants (Lithocarpus glaber, Camellia fraterna, Machilus thunbergii, Symplocos sumuntia), and competitive plants (Cinnamomum subavenium, Elaeocarpus decipiens, Ternstroemia gymnanthera, Eurya hebeclados). The contents of C, N, P and K were measured and the stoichiometric ratios were calculated. The results showed that: (1) The P contents in the rhizosphere soils of S. zhejiangensis and the synergistic plants were 1.28 g·kg⁻¹ and 1.22 g·kg⁻¹, respectively, which were significantly higher than those of the competitive plants (0.85 g·kg⁻¹) (P＜0.05). However, there was no significant difference in soil C, N and K contents among the three types of plants. (2) The soil C/P, N/P, and K/P ratios in the rhizosphere soil of competitive plants were 32.23,1.41 and 10.56, respectively, which were significantly higher than those of S. zhejiangensis and synergistic plants (P＜0.05). There was no significant difference in soil C/N, C/K, or N/K ratios among the three types of plants. (3) The C content in soil was significantly positively correlated with the N content (P＜0.01), while C content and N content were significantly negatively correlated with P content, C/P and N/P ratios (P＜0.01). In conclusion, the synergistic plants may alleviate the phosphorus limitation for S. zhejiangensis during the growth by maintaining higher soil P content, while the competitive plants tended to compete for the limited phosphorus resources in the soil. For the conservation of this species, it was recommended to apply the phosphorus fertilizer appropriately, thin out the competitive plants moderately, and replant the synergistic plants to improve its habitat conditions.