Abstract: Using the conventional chemical analysis technology, the contaminant content in wastewater from different treating stages in two representative large-scale pig farms in Guangxi was determined and they were compared with the national discharged standards. The changes of contamination indices in every treating link were investigated, so as to provide references for taking according measures for energy conservation and emission reduction in the livestock breeding. Contaminants indices included suspended solids （SS）, ammonia nitrogen （NH3-N）, BOD5 and chemical oxygen demand （CODcr）. The results showed that the wastewater discharged from Farm 1 after applying wastewater treatment technology was substandard,but the wastewater discharged from Farm 2 reached standard. Wastewater could be purified by plants grew in the pond. And the suspended solids （SS）could be effectively reduced by the treatment in the settling tank and secondary sedimentation tank.