Abstract: An actinomycete strain HNU-1, isolated from a farmland soil in Shou county, Anhui province, exhibited antifungal activity against Botrytis cinerea. Based on characteristics, in morphology, physiological, biochemica and 16S rRNA gene sequences, the strain was identified as Streptomyces hygroscopicus. Culture filtrate of the strain could inhibit mycelium growth and spore germination of B. cinerea, and resulted in more inhibition as the concentration of the culture filtrate increased. Mycelium growth and spore germination of B. cinerea was completely inhibited by 6.67-fold dilution of the culture filtrate. Pot experiments demonstrated that prevention and cure efficiencies of 6.67-fold dilution of the culture filtrate against tomato gray mould were 87.8% and 77.9%, respectively, significantly superior to those of 500-fold dilution of 50% Badistan.