Abstract: Biological characteristics of pathogenic Fusarium oxysporum, which causes stem rot disease on Cymbidium ensiflium, were studied. Effects of temperature, pH, light, and carbon and nitrogen sources on the hyphal growth and sporulation of the pathogen were examined. In addition, the lethal temperature and time of F. oxysporum spores were determined. The results showed that the optimal conditions for the growth and sporulation of the pathogen were 25℃, pH 7, 12-h-L:12-h-D exposure, lactose monohydrate for carbon, and NaNO₂ for nitrogen. The lethality of the spores was 5 min in 55℃ water. The study provided reference for the effective control of stem rot on C. ensifolium.