In this research, we did not use any template, but a prickly structure urchin like morphology made of composite TiO2/g-C3N4 was synthesized by a one-step solvothermal method. It is generally reported that TiO2 is a pure phase, besides, the photocatalytic effect of multiphase TiO2 will be better. After the g-C3N4 was successfully loaded on the TiO2 surface, the morphology did not change. The special sea urchin morphology provides more active sites for catalysis. The band gap becomes smaller, because two materials were combined to form an interface effect. Meanwhile, it could effectively separate electron hole pairs, and promote charge transfer efficiency. More active substances were produced under visible light, such as superoxide radicals and holes. The scavenging experiment further confirms that superoxide radicals and holes play an important role in the catalytic process. The photocatalytic degradation of ibuprofen under visible light was improved. A possible enhanced photocatalytic mechanism of g-C3N4/TiO2 heterojunction photocatalysts was proposed. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.