[Objective] The influence of alder and cypress on the weathering and nutrient characteristics of purple soil profiles in the hilly area of Central Sichuan Province was analyzed, in order to provide a scientific basis for soil erosion control and agricultural production.[Methods] The Wanan basin in the hilly area of Central Sichuan Province was selected as the study area, and alder and cypress were used as the study objects. Field survey and profile excavation were conducted to study the effects of alder and cypress on the weathering and nutrients of purple soil profiles.[Results] ① The profile fractal dimension of alder and cypress were 2.07 and 2.13, respectively, which increased by 6.47% and 9.03%, respectively, compared with the control, among which the effect of cypress was better than that of alder. ② The differences in chemical weathering between alder, cypress, and control profiles were not significant. Alder and cypress growth has less effect on chemical weathering of the profile. ③ The integrated fertility index of alder and cypress profile increased by 14.08% and 11.27%, respectively, compared with the control. Alder showed a better enhancement effect than cypress, which was especially obvious in organic matter, total N, alkali-hydrolyzable N, and effective K. ④ The root distribution density of alder and cypress showed a significant positive correlation (p<0.05) with the profile fractal dimension and the integrated fertility index, however, the correlation with chemical weathering index was not significant (p>0.05).[Conclusion] Alder and cypress significantly promote the physical weathering rate and nutrients characteristics of purple soil in the hilly area of Central Sichuan Province.