The eleven isolates were isolated from the roots of Cymbidium goeriingii inhabited in the island of Cheju and from Cypripeium calceolus inhabited in the mountains around ChungPuk. The isolates were inoculated to the plantlets of commercial orchids and evaluated to be symbiotic with the orchids. Also, their genomic DNA was extracted from the cultures on the agars and reacted with the primers selected, understanding their biological relations with the pathogenic fungi. Out of eleven isolates, three were observed to stimulate the growth of the orchid plantlets and to be biologically related to the orchid symbiotic fungi, as based on the analyses of PCR-RAPD. Otherwise, the others were observed to decline the growth of orchid plantlet, compared with those of control, and to be grouped with the pathogenic. As based on the results of this work, the roots of C. goeriingii were found to be frequently infected with the pathogenic fungus rather than with symbiotic fungus in natural systems. Further, the infection of the commercial orchid with the pathogens was believed to be abundant without any inoculation of symbiotic fungus under the conditions of greenhouse.