The fungal strain CL-3 was isolated from the root of wild Cymbidium goeringii with using conventional isolation method. The inoculum of strain CL-3 was used to study its interaction with its host plant. According to the morphological features examination and rDNA ITS sequence analysis, the closest relative of the strain was Acremonium strictum, with the similarity of 100%. After two months of symbioses culture, the fresh biomass of C. goeringii inoculated with CL-3 increased by 80.5%, and the endophytic CL-3 was re-isolated from the seedlings. The statistics showed that the difference between inoculation group and control group was significant. The presence of the fungus in the tissues was stud-ied with paraffin-cut section. The results showed that the fungus was observed in inner tissues of roots, indicating that the symbiosis relationship between Cymbidium goeringii and fungi could be established.