The test adopted the rapid sewage sanctifier for treating dairy wastewater with the coagulants of AS and PAC.Relation of dosage and the removal rates of turbidity and COD was investigated,and the optimized dosage of AS and PAC is 390 mg/L and 320 mg/L,respectively.At the same time,the synergism of the best inorganic coagulation PAC and organic flocculator polyacrylamide(PAM) in sewage treatment was studied,PAC(240 mg/L)+ PAM(0.5mg/L)is the best and the most economic combination.