Abstract: By the experimental procedure of enrichment culture and purification, one bacterial strain F1 was screened from the soil of tea garden in Shandong province. The strain was identified as Flavobacterium sp., on the base of 16S rRNA sequencing analysis and physiological ＆ biochemistry tests as well as the observation of negative staining electron microscopy. The nitrification performance and denitrification ability were studied and the results showed that while using organic matter, strain F1 has the function of both nitrification and denitrification. After 60 h culture, ammonia nitrogen removal rate reached 84.54% and nitrite nitrogen removal rate reached 91.87% in the nitrifying medium; ammonia nitrogen removal rate reached 79.17% and nitrite nitrogen removal rate reached 84.30% in the denitrifying medium; the denitrification capacity of ammonium nitrogen was the strongest under the conditions of the initial nitrogen.