Abstract: The Helicobasidium mompa Tanaka is one of the most important plant pathogenic fungi that cause root disease in Peony. An approach of combining fixed observation with field investigation, and isolation, culture in laboratory was used to study the biological Characteristics of peony Helicobasidium mompa Tanaka. Control measures were provided by lab toxigenicity testing and field fungicide efficacy. Results showed that the disease was prevalent from the last ten-day period of March to the middle ten days of May, the most suitable pH of pathogenic was almost 5.8 and temperature ranged from 25~26℃. Toxigenicity testing proved that bacteriostatic rate was 93.7% with 70% Thiophanate-methyl and 91.4%with 45% Amobam. The best control effects was 1000ml 70% Thiophanate-methyl with 1000 dilute rate per plant, and 1000ml 45% Amobam with 1000 dilute rate per plant.