Endophytic microorganisms can form a reciprocal symbiosis relationship with plants, and some can improve the survival ability of plants in adversity and promote plant growth and development. In order to further understand the isolation of blueberry endophytic fungi, mycorrhizal fungi that promote the growth of blueberries were screened out. In this paper, blueberry root samples were collected from 5 places in Guizhou Province, and the endophytic fungi were identified by morphological and molecular biological methods. The types of mycorrhizal fungi were determined by the way of back-joining method. Based on the mycorrhizal infection, several kinds of easy culture and energy were selected. A strain that effectively infects blueberry plants and promotes the growth and development of blueberries. The results showed that a total of 995 endophytic fungi were isolated from 5 regions in Guizhou, which were divided into 42 genera, of which Chaetomium spp. and Fusarium spp. were the most dominant, representing 22.91% and 16.18% respectively, followed by Phialocephala spp. (9.54%). Through literature reviewed and tie-back experiments, 9 types of mycorrhizas (Y-037, Y-007, Y-078, Y-017, Y-026, X-065, Y-079, Y-012, Y-005). Among them, Y-037 has the strongest infection intensity and significantly promotes plant growth. This research provides a theoretical basis for proposing a set of efficient and mature blueberry mycorrhizal cultivation technology.