Taking the annual seedlings of Xanthoceras sorbifolia infected by root knot nematode (Meloidogyne incognita) as materials, we observed the morphology and microstructure of root system, plant growth and development and the distribution characteristics of main mineral nutrients in the seedlings, analyzed the relationship between different mineral elements and nematode infection, and clarified the effect of root knot nematode on the growth and development characteristics of X. sorbifolia seedlings. The results showed that: (1) root knots were formed in the seedlings infected with root knot nematodes, which were divided into grade 0 (control, normal plants), grade 2, grade 3 and grade 4 according to the degree of root knot occurrence. The root anatomical structure of X. sorbifolia plants with root nodes showed typical changes: the cortex is relatively thick, the xylem is twisted, the vessels are less, and the rays were less and not evenly distributed. The contents of phloem cells were significantly more. Several giant cells and cell cavities were mainly found in phloem. (2) Compared with the control, the height and ground diameter of seedlings with root knot increased significantly (P<0.05). (3) The contents of N and P in roots, stems and leaves all decreased, and the contents of N in roots with grade 2, 3 and 4 roots decreased by 7.8%, 16.0% and 29.5%, and the content of P decreased by 15.6%, 7.1% and 43.3%, respectively, compared with normal plants. The contents of Fe and Zn in roots increased significantly. The content of Fe in roots of different roots increased 1.56, 0.81 and 3 times, respectively, and the content of Zn in roots increased 1.11, 1.56 and 1.78 times, respectively, compared with normal plants. Compared with normal plants, K content in roots of seedlings with grade 3 and 4 root knots significantly increased (P<0.05), while K content in leaves of seedlings with grade 2 and 4 root knots significantly decreased by 61.5% and 47.0%, respectively. (4) Overall analysis showed that N content in roots and stems had the most obvious response to rootknot nematode infection, and its content decreased with the increase of infection degree. There was a significant negative correlation between leaf Mg content and infection rate, and K content and seedling biomass (P<0.05). This study provided a theoretical basis for the effect of rootknot nematodes on nutrient uptake and utilization of X. sorbifolia seedlings.