The potential health hazards of trihalomethanes (THMs) contamination in drinking water in Shenzhen were estimated. The concentrations of THMs in drinking water from 13 centralized water supply systems were determined from Jan 2015 to Dec 2016 in Shenzhen. The water environmental health risk assessment model recommended by USEPA was established based on the water monitoring data of THMs. Preliminary health risks of THMs through ingestion of drinking water were assessed. The median concentrations of THMs, TCM, DBCM, BDCM and TBM in drinking water were 37.0, 24.5, 2.3, 7.8 and 0.3 ¦Ìg/L respectively. The values of carcinogenic risks for THMs, TCM, DBCM, BDCM, and TBM to the individual per year in drinking water were 4.52 ¡Á 10^-5, 2.38 ¡Á 10^-5, 6.07 ¡Á 10^-6, 1.52 ¡Á 10^-5 and 7.45 ¡Á 10^-8 respectively. The values of non-carcinogenic risks for THMs, TCM, DBCM, BDCM and TBM to the individual per year in drinking water were 9.32 ¡Á 10^-2, 7.68 ¡Á 10^-2, 3.61 ¡Á 10^-3, and 1.23 ¡Á 10^-2 and 4.71 ¡Á 10^-4 respectively. The health risk caused by THMs to the individual through ingestion of drinking water was in the order of TCM, BDCM, DBCM and TBM from high to low. The carcinogenic risks induced by THMs through ingestion of drinking water are acceptable with tolerable value offered by USEPA (1.0 ¡Á 10^-6 - 1.0 ¡Á 10^-4), but reached to the tolerable value (5.0 ¡Á 10^-5) by International Commission on Radiological Protection (ICRP). The non-carcinogenic risk of THMs is tolerable (HI < 1).