In this study, experiments were conducted to make a comparison in bromate formation between KMnO4/O3 combined oxidation and single ozonation. The effect of KMnO4 dosage, temperature, pH and NOM on bromate formation during KMnO4/O3 combined oxidation was investigated. Result shows that, bromate formation is 26% lower during the process of KMnO4/O3 combined oxidation. The optimal KMnO4 dosage is suggested to be 1mg/L considering balance between bromate inhibition and the residual manganese concentration. When KMnO4 dosage was 1.0mg/L, initial bromide concentration was lower than 80 μg/L, and temperature was below 25°C, combined oxidation can make the formation of bromate under the maximum contaminant level of 10 μg/L. Finally, the probable mechanism of the better behavior of KMnO4/O3 combined oxidation was discussed.