Abstract: In order to treat coal gasification wastewater of high ammonia-nitrogen with high efficiency and low cost, the technology of shortcut simultaneous nitroge n removal was used to conduct an experiment. The factors on nitrogen removal effects by start-up procedure, nitrogen transformation characteristics and major factors ( hydraulic retention time, dissolved oxygen, carbon-nitrogen ratio) were analyzed. The results indicated that the reactor finished start-up of shortcut simultaneous nitroge n removal in 29 d of cultivation time. The NH4*-N removal rate, cumulative NO-2-N rate and simultaneous nitrification-denitrification rate respectively reached to 99.6%, 81.3% and 49.4%in the last phase of start-up procedure. To remove NH4*-N with the technology of shortcut simultaneous nitrogen removal efficiently and steadily, hydr aulic retention time, dissolved oxygen, carbon-nitrogen ratio should be controlled with 28.0 ~ 32.7 h、1.0~ 1.5 mg/L and 4 8. Under the optimum condition, the NH4*-N removal rate, cumulative NO-2-N rate and simultaneous nitrification-denitrification rate respectively reached to 98.1%, 81.2% and 76.1%.