Abstract: Microwave radiation technology was used to treat paper waste water.Using FeSO₄-loaded slag as the wave-absorbing and oxidation-catalyzing carrier,microwave radiation could effectively decompose organic pollutant in paper waste water.The activity of slag treated by microwave was better than that by normal furnace.The optimal conditions were determined by orthogonal experiment: the consumption of supported slag was 28 g per 50 mL waste water,time of microwave treatment was 17 min,and power of microwave radiation was 800 W.Under the optimal conditions,the removal rate of COD could reach 95%.The activated slag was reused,and some must be damaged;therefore the removal rate of COD declined.