【Objective】Wheel wingnut (Cyclocarya paliurus), native to China, is the sole species in its genus. Grown for its medicine food homologous and fine timber tree species as well as for an ornamental plant, there exists a great development and application prospect for C. paliurus resources. This study explores the responses of soil nutrients, soil enzymes activities and leaf nutrients to combined application of biochar and organic fertilizer in a compound system of C. paliurus and tea(Camellia sinensis), to select an optimal application mass ratio of biochar and organic fertilizer, and to provide organic cultivation scheme for the management of C. paliurus and tea compound system.【Method】A completely randomized block design was established in the compound system of C. paliurus and tea, comprising five treatments with different application mass ratios of biochar and organic fertilizer: CK (no fertilization), T1 (100% organic fertilizer, as 4 500 kg/hm²), T2 (15% biochar + 85% organic fertilizer, as 675 kg/hm²+3 825 kg/hm²), T3 (30% biochar + 70% organic fertilizer, as 1 350 kg/hm²+3 150 kg/hm²), and T4 (50% biochar + 50% organic fertilizer, as 2 250 kg/hm²+2 250 kg/hm²). The study examined the effects of these treatments on soil nutrients and enzyme activities across different soil layers ((0,10], (10,20], and (20,40] cm), as well as on the leaf nutrient content of both plant species.【Result】Two-way ANOVA indicates that both different fertilization treatments and soil layer depth have significant impacts on soil pH (P<0.05). With the increase of biochar application ratio, soil pH in the surface layer (0,10] cm significantly increases (P<0.05). Compared with CK treatment, the treatment with T4 increases the pH by 12.89%, 4.50% and 3.13% in the soils of (0,10], (10,20] and (20,40] cm respectively. Application of biochar combined with organic fertilizers significantly affects soil nutrients (P<0.05). Compared to the CK, the combined application of biochar and organic fertilizer significantly increases both the soil total and available nutrient contents of nitrogen and phosphorus in the soil (P<0.05), and shows a trend of first increasing and then decreasing with increasing biochar application ratio. Both fertilizer treatments and soil layer depth have a highly significant effect on soil enzyme activities (P<0.001). Combined application of biochar and organic fertilizer also significantly enhances the activities of β-glucoside (βG) and acid phosphatase (ACP) in the soil layers of (0,10] cm (P<0.05), which all reach the maximum values at the T2 treatment and significantly increase by 22.6% and 47.0% respectively when compared with CK treatment. In general, the activities of βG, NAG and ACP show a decreasing trend with the increase of biochar addition. Different treatments have significant effects on leaf nutrient contents of nitrogen and phosphorus in C. paliurus (P<0.05). The highest N content in C. paliurus leaves is observed under T3 treatment, with 12.4% greater than the CK, while the lowest P content is detected under T4 treatment and the highest P content is under T1 treatment (about 6% higher than T4 treatment). However, no significant effect on nutrient contents of nitrogen and phosphorus in tea leaves is detected among different treatments (P>0.05), with the maximum value appearing in the T2 treatment as a whole. The partial least squares path modeling (PLSPM) analysis results show that the effects of combined application of biochar and organic fertilizer on soil pH and soil enzyme activity are highly significant positive regulation (P<0.01), and the path coefficients reach 0.899 and 0.752 respectively. Meanwhile, a combined application of biochar and organic fertilizer can increase the content of available nitrogen and available phosphorus in soil by improving soil pH and soil enzyme activity, and soil available nutrients have a significant positive effect on the plant leaf nutrient uptake.【Conclusion】A reasonable combined application of biochar and organic fertilizer can significantly improve soil pH and soil enzyme activity, accelerate soil nutrient conversion, and promote nutrient uptake and utilization of C. paliurus and tea tree, while the application mass ratio of 15% biochar and 85% organic fertilizer can achieve the effect. However, the proportion of such combined application should be continuously improved based on the site conditions and stand ages.