A highly active denitrifier named GW1was isolated from the denitrification granule sludge, and 16S rDNA identification of the strain was performed. Influencing factors such as temperature, pH, carbon source and C/N ratio were optimized through batch experiments,and the effect of nitrate concentration on the denitrification was also studied. The phylogenetic analysis based on 16S rDNA suggests that strain GW1is the closest relative of Paracoccus versutus with 99.9% sequence similarity and high homology. Genbank sequence number is GU111570. Strain GW1is Gram-positive. The optimal conditions for the denitrification by strain GW1are sodium succinate as carbon source, temperature 35~40℃, pH(7.0~8.0)and proposed project use of C/N ratio 3, respectively. Strain GW1can remove nitrate effectively. The study may help solve the problem of slow denitrifying rate.