A heterotrophic nitrification-aerobic denitrification bacterium named HY3-2 was isolated from the high-salt aerobic granular sludge system. The morphological observation and 16S rDNA sequence analysis showed that HY3-2 was Klebsiella quasipneumoniae subsp.quasipneumoniae. The removal characteristics of ammonia nitrogen, nitrate and nitrite by HY3-2 were studied. The results showed that the strain had good heterotrophic nitrification and aerobic denitrification performance, and the removal rates of ammonia nitrogen, nitrate and nitrite were 63.57%, 88.11% and 98.38% respectively. The study on the nitrogen removal performance of the strain showed that:HY3-2 used glycerol as carbon source. Under the condition (C/N 25, temperature 20℃ or 30℃, rotation speed 150r/min, initial pH 7~10, salinity less than 50g/L), the effect on NH₄⁺-N removal with the concentration of 100mg/L was good, and the removal rate was 90.7%. When the sodium citrate was used as carbon source (C/N 25, temperature 30℃, rotation speed 150r/min, initial pH 5~9), the aerobic denitrification can be performed when the salinity was less than 15g/L, the NO₃^--N removal rate was over 99%.