Based on the monitoring experiment of pollutant production from a typical scale pig farm in three pig feeding stages(sows, fattening pigs and piglets) in the Taihu Lake region, Jiangsu Province, the contents of pig manure pollutant and the coefficients of the pollutant production from pigs were estimated. In addition, discharge of animal manure pollutant and the water equal standard pollution index in the region in 2011 were estimated using animal manure discharge rate and equal standard pollution method. Results showed that the total discharge amount of total nitrogen(TN), total phosphorus(TP) and chemical oxygen demand(COD) from livestock and poultry breeding industries was 218.9 thousand tons, and the water equal standard pollution indexes of Changzhou, Suzhou and Wuxi Cities were 11.54, 5.70 and 6.10, respectively. However, differences were observed for the water contamination degree in different areas. The primary pollution source of livestock and poultry breeding industries was poultry and pigs whose load ration in equivalent standard reached 49.52% and 44.47%, and the primary pollutant was TP whose load ration in equivalent standard reached 67.87%. A great attention should be paid to the pollution of P.