The paper discussed the effects of ozonation on the trihalomethane formation potential (THMFP) and trihalomethane species in bromide-containing water, with humic acid as precursor of disinfection byproducts. The results demonstrated that higher concentration of bromide ions in raw water is favorable to increase of proportion of THMFP and brominated trihalomethanes (THMs-Br). However, once bromide-containing water was oxidized by ozone, part of bormide ions would be oxidized into bromate, and the incorporation of bromide to THM reduces thusly. The intermediate products of humic acid formed during oxidation are quite complex, which perhaps increases the yield of precursors of disinfection byproducts (DBPs) on the contrary. Only with higher ozone dosage, reduction of the total THMFP can be achieved. However, the bromate byproducts produced during oxidation were considered to be potential human carcinogens, which restricted the application of ozone in drinking water. The yield of bromate and THMFP would be reduced significantly as long as ammonia nitrogen is present in bromide-containing water during ozonation.