NOVELTY - A large-scale pig farm wastewater treating method involves introducing pig farm wastewater into a biogas digester, filtering and transporting the wastewater to an adjusting tank, and adding an alkali solution to the adjusting tank. A primary sedimentation process, an anaerobic treatment, a secondary precipitation process, biochemical treatment are performed. The wastewater is transported to a reaction tank and subjected to a flocculation precipitation treatment and a final precipitating process. The wastewater is transported to a disinfection tank for performing a disinfection process.    USE - Method for treating wastewater in a large-scale pig farm.    ADVANTAGE - The method enables treating the wastewater in a simple and cost-effective manner.    DETAILED DESCRIPTION - A large-scale pig farm wastewater treating method involves introducing pig farm waste water into a biogas digester for performing anaerobic fermentation, filtering the wastewater by a grizzly screen, transporting the wastewater to an adjusting tank, and adding an alkali solution to the adjusting tank for controlling pH value of the wastewater at 6.5-7.5. Initial precipitation of the wastewater in the adjusting tank is pumped into a primary sedimentation tank for performing a primary sedimentation process. The wastewater is transported to an anaerobic tank for performing anaerobic treatment for 12-22 hours followed by performing a secondary precipitation process for 2-3 hours. The wastewater is transported to an A/? tank for performing A/O biochemical treatment and transported to a secondary sedimentation tank for performing a deposition process, and residual sludge is discharged into a sludge pool. The wastewater is transported to a reaction tank and subjected to a flocculation precipitation treatment by adding a flocculating agent. A final precipitating process is performed in the reaction tank. The wastewater is transported to a disinfection tank for performing a disinfection process by adding a disinfectant.