A strain,Actinobacillus succinogenes CGMCC 1593,producing succinic acid was isolated from bovin rumen,which could pro- duces succinic acid by anaerobic fermentation.A series of morphological and biochemical characteristics and sequence analysis of 16S rDNA reveal that it belongs to Actinobacillus succinogenes.When cultured anaerobically in medium containing 60 g/L glucose as carbon source,the strain produces 25.8 g/L of succnic acid.