The purpose of this study was to explore the relationship between the soil fungal community structure and function and soil chemical properties and enzyme activity in Pinus tabuliformis sand-fixing forests of different ages, so as to provide a theoretical basis for the rational management and protection of P. tabuliformis sand-fixing forests. Taking the mobile sand of Horqin Sandy Land as the control (0 year), P. tabuliformis forests with sand fixation for 18, 34, 48 and 56 years were selected as the research objects, and high-throughput sequencing technology was used to analyze the differences in soil fungal community structure and functional groups. The results show: (1) The 2517 OTUs obtained from the soil of the P. tabuliformis sand-fixing forest belong to 14 phyla, 48 classes, 127 orders, 286 families, and 579 genera of fungi. The dominant phyla were Ascomycota (47.91%-67.34%), Basidiomycota (18.45%-43.70%), and Mortierellomycota (1.41%-8.36%); the dominant genera were Biappendiculispora, Scleroderma, Tomentella, Knufia, and Amphinema. (2) Venn diagram and NMDS analysis showed that afforestation has a greater impact on soil fungal community structure. The ace index and chao index of soil fungi at each stand age increased significantly (P<0.05), and were related to organic matter, total nitrogen, and total phosphorus, urease, dehydrogenase, catalase, neutral phosphatase, sucrase and neutral protease have a significant positive correlation (P<0.05). (3) The fungal community was mainly composed of symbiotic and saprophytic types. After afforestation, the relative abundance of symbiotic types increased compared with the control, while the relative abundance of saprophytic types was relatively stable. Afforestation plays an important regulatory role on the structure and function of soil fungal communities. The research results enrich the research content of soil microbial communities in sand-fixing forests and provide a basis for soil health evaluation of P. tabuliformis sand-fixing forests in Horqin Sandy Land.