Abstract: The objective is to select actinomycete which has strong antagonistic ability against winter jujube ring grain disease. Total 198 actinomycetes were isolated by culture-dependent method from the shell sediment in the Seashell Islands of Yellow River Delta，and the strain BK with the strongest antagonistic ability was further studied. Strain BK was identified based on its morphology，physio-biochemical characters and 16S rRNA sequence analysis，and its ability against winter jujube ring grain disease was also studied，providing a theoretical basis in biological control of winter jujube ring grain disease. The results showed that BK significantly inhibited the mycelium growth of Macrophoma kuwatsukai，with inhibitory rate of 72.3%. The control effect of the culture filtrate against winter jujube ring grain disease was 73.7%，which had no significant difference from that by the 50% carbendazim. Strain BK was identified as Streptomyces purpureus. To sum up，strain BK is an ideal antagonistic one，and presents a potential application for the biological control of winter jujube ring grain disease.

Key words: Seashell Islands of Yellow River Delta, antagonistic actinomycete, winter jujube, ring grain disease, inhibitory effect