•Actual wastewater is of great significance for reclaimed-water recycling.•Dispersion and reactivity of NZVI-supported were enhanced compared to NZVI alone.•Removal processes of THMs presented different tendencies by AC, NZVI and NZVI/AC.•NZVI/AC showed increased performance on THMs removal due to synergetic effect. Zero valent iron/activated carbon nanocomposite (NZVI/AC) was synthesized and applied for trihalomethane (THM) removal in this study. The performance of NZVI/AC, with respect to characterization, removal kinetics and isotherms, was compared with that of activated carbon and nanoscale zero-valent iron. The results showed that the size of NZVI became smaller when immobilized on AC, which was in the range of 30–70nm, and meanwhile with activated carbon as a support, NZVI/AC possesses higher dispersion, better stability and reactivity. Results of kinetic experiments indicated that NZVI/AC showed the best trihalomethane removal capacity, followed by NZVI and AC. The synergetic effect of prompt adsorption of trihalomethanes to NZVI/AC phase and the reduction of THMs by Fe0 on NZVI/AC was recognized as removal mechanism of the THMs. Therefore, NZVI/AC could be used as a potential material to remove trihalomethane in wastewater treatment process, which of great significance for reclaimed-water recycling.