In view of the problem that most nitrogen removal microorganisms are difficult to effectively remove nitrogen from sewage in winter at low temperature, a strain D15 with high efficiency of heterotrophic nitrification and aerobic denitrification(HN-AD) at 10-15 ℃ was isolated from the soil of flooded rice fields in winter. Strain D15 was identified as Pseudomonas alcaliphila. The effects of nitrogen source concentration (100, 150, 200, 250, 300, 400, 600, 800 mg/L), carbon sources type (trisodium citrate, sodium succinate, sodium acetate, sodium oxalate, maltose), shaking table speed (130, 150, 170, 190, 210 r/min), and culture temperature (5, 10, 15, 20, 25, 30, 35 ℃) on nitrogen removal efficiency of strain D15 were investigated. The results showed that the removal rate of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen of strain D15 reached 100.0% under the conditions of using trisodium citrate as carbon source, initial nitrogen source mass concentration of 150 mg/L, shaking table speed of 190 r/min with a culture temperature of 15 ℃. After adding trisodium citrate to pig manure wastewater, the wastewater was incubated with D15 strain at 15 ℃ for 54 h and 66 h respectively, the removal rates of ammonia nitrogen and total nitrogen from the wastewater by D15 strain reached 100.0% and 88.8% respectively.