As a high‐efficient photocatalyst, g‐C3N4/TiO2 (PCN) was successfully prepared by thermal polymerization. In addition, the structure and morphological characteristics of the as‐prepared samples were investigated by XRD, BET, XPS, SEM, TEM, and UV‐vis DRS. The results revealed that in the presence of g‐C3N4, the physicochemical properties of the catalyst and the band gap of PCN decreased from 3.09 eV to 2.98 eV, clearly indicative of the enhanced photocatalytic performance relative to pure P25 or g‐C3N4 under sunlight. Furthermore, the photocatalytic properties of PCN were examined by the degradation of pyridine and other nitrogen heterocyclic pollutants under sunlight irradiation. Next, the main factors affecting the photocatalytic activity were investigated in detail, including the initial concentration of the pollutant, the mass of the photocatalyst, the initial pH of the solution, and the doping amount of g‐C3N4, as well as different free‐radical scavengers. On the other hand, the reusability of PCN demonstrated that photocatalysts exhibit outstanding photocatalytic stability after 10 cycles. Hence, high efficiency photocatalysts demonstrate potential for industrial applications such as sewage treatment. [ABSTRACT FROM AUTHOR]