Nitrous oxide (N_2O) emission can be affected by the amounts and forms of nitrogen (N) available in soils. To improve our understanding of the response of N_2O emission to different N addition levels and forms, a manipulative field experiment was conducted to investigate the effects of different forms (ammonium sulfate, As:(NH_4)_2SO_4; sodium nitrate, Na:NaNO_3; ammonium nitrate, AN:NH_4NO_3) and levels (control: 0kg/(ha·year); low N, LN: 50kg/(ha·year); MN: 100 kg/(ha·year) and high N, HN: 150kg/(ha·year)) of N addition on N_2O emission of temperate Pinus tabuliformis forest soil using the static closed chamber method at Experimental Forest Station of Beijing Forestry University in Beijing, northern China. Our results showed that soil N_2O emission showed a trend of seasonal variation: higher in summer (May to August) but relatively low in the remaining seasons. The minimum value appeared in January. Different levels of N addition increased annual N_2O emission in the order of HN>MN>LN>control. The three N forms increased annual N_2O emission in the order of AN>As>Na, but the difference was insignificant (P>0.05) between As and AN or As and Na. These results suggested that the N_2O emission from temperate forest soil sensitively responded to N addition forms and levels. In addition, soil temperature, air temperature and water-filled pore space also influenced soil N_2O fluxes. Annual soil N_2O emission factors ranged from 0.34% to 0.94% for different N addition treatments, with an overall emission factor value of 0.364%. The emission factor values were far less than the mean default emission factor proposed by the Intergovernmental Panel on Climate Change (IPCC).