This paper reports that hybrid titanium dioxide (TiO2) packaged self-assembly perylenetetracarboxylic acid diimide (PTCDI) by self-assembly. These were synthesized through simple mechanical milling that has great photocatalytic performance under visible light. The PTCDI@TiO2 composite had high activity for the degradation of phenol and 2,4-dichlorophenol, which were 2.3 and 3.2 times of the monomer PTCDI, respectively. After three cycles, the activity of the composite catalyst remained at 70%. Further analysis showed that the photocatalytic activity and stability are mainly due to the enhancement of the charge mobility by the pi-pi conjugated structure in PTCDI. Moreover, the good energy level matching between PTCDI and TiO2 helps to separate the electron-hole, thus improving the photocatalytic performance of the composite. The origin of photocatalytic activity was greatly improved due to holes and O-center dot(2)-, which was mainly attributed to the strong interaction between PTCDI and TiO2.