This study was conducted to assess the effect of acidification of pig slurry on nitrogen (N) mineralization and its environmental impacts during pig slurry fermentation. Different inorganic and organic acids were used to acidify pig slurry. Four treatments including non-acidified pig slurry (control), pig slurry acidified with sulfuric acid, lactic acid, and citric acid were allocated with three replications. The total N content in the acidified pig slurry was higher than non-acidified pig slurry after fermentation. Acidification tended to increase total N content in pig slurry. Ammonium N (NH4 +-N) released from pig slurry was obviously increased at 7 days after incubation, representing 61.4%, 36.8%, and 37.4% increase in the acidified pig slurry with sulfuric acid, lactic acid, and citric acid, respectively. Nitrate N (NO3 --N) in the acidified pig slurry with sulfuric acid was the highest throughout the experiment period, but non-significant effect of organic acid. A large portion of ammonia (NH3) emission occurred within 10 days, corresponding to more than 55% of total NH3 emission. Total cumulative NH3 emission during the experimental period was lower 91% (2.9 mg N kg-1), 78% (7.3 mg N kg-1), and 81% (6.2 mg N kg-1) in the acidified pig slurry with sulfuric acid, lactic acid, and citric acid, respectively, than non-acidified pig slurry (32.7 mg N kg-1). These results suggest that acidification of pig slurry (particularly with sulfuric acid) can be faced as a good strategy to reduce NH3 emission without depressing the mineralization process.