Abstract: On the basis of the research on the site condition of mineral yellow soil in the early stage, the purple soil walnut planting area in Xide County of Liangshan Prefecture was selected to carry out the fertilizer contrast experimen, in order to put forward reasonable fertilization suggestions for walnut planting in the purple soil widely distributed area. The 4-year-old "shuoxing" saplings and 10-year-old hanging fruit trees were selected as the experimental materials, and four treatments (T1: no fertilization, T2: application of common compound fertilizer, T3: application of special inorganic fertilizer, T4: application of compound microbial fertilizer) were set up to explore the effects of special compound microbial fertilizer on the plant height, fruit yield, quality and economic benefits of young trees. The results showed that the application of special compound microbial fertilizer could increase the height and fruit yield of young walnut trees. The growth of young walnut tree height and fruit yield in purple soil was higher than that in mineral yellow soil. The application of compound fertilizer was 38.03% higher than that of no fertilizer, 27.27% higher than that of common compound fertilizer and 10.11% higher than that of inorganic special fertilizer. The yield of walnut fruit increased by 44.56% and 28.04% compared with no fertilizer and common compound fertilizer, and the transverse diameter, weight, kernel yield, fat content and protein content of walnut fruit increased by 10.99%, 14.89%, 10.31%, 8.09% and 7.27%, respectively.