Photocatalytic degradation of 2, 4-dichlorophenol (DCP) using granular activated carbon (GAC) supported TiO2 (Ti–GAC, using sol–gel method) is investigated. Operation parameters including annealing temperature, catalyst loading, air flow rate, initial pH and DCP concentration are optimized. The results show that DCP removal increases with the increase of Ti–GAC while decreases with the increase of initial DCP concentration. DCP is removed much faster in neutral conditions than in acidic or alkaline conditions. Comprehensive comparison among adsorption, photolysis and photocatalysis in DCP removal is conducted to reveal the synergistic effect in the photocatalysis process, and the results indicate that the DCP is removed by the joint effect of adsorption and HO∙ oxidation. In addition, the photocatalysis is applied in a continuous form to treat DCP polluted real raw water for drinking water production, and it is found to have potentially advantageous on dissolved pollutants in drinking water, and would have great potential for a wide range of practical applications.