The Bi4Ti3O12/g-C3N4 composites with microsheet and nanosheet structure were prepared through facile ultrasonic-assisted method. The SEM and TEM results suggested that the nanosheets g-C3N4 were stacked on the surface of regular Bi4Ti3O12 sheets. Comparing with pure Bi4Ti3O12 and g-C3N4, the Bi4Ti3O12/g-C3N4 composites showed significant enhancement in photocatalytic efficiency for the degradation of RhB in solution. With the mass ratio of g-C3N4 increasing to 10 wt%, the Bi4Ti3O12/g-C3N4-10% presented the best photocatalytic activity. Its photocatalysis reaction constant was approximately 2 times higher than the single component Bi4Ti3O12 or g-C3N4. Meanwhile, good stability and durability for the Bi4Ti3O12/g-C3N4-10% were confirmed by the recycling experiment and FT-IR analysis. The possible mechanism for the improvements was the matched band positions and the effective separation of photo-excited electrons (e(-)) and holes (h(+)). Furthermore, based on the results of active species trapping, photo-generated holes (h(+)) and superoxide radical (center dot O-2(-)) could be the main radicals in reaction. (C) 2018 The Chemical Industry and Engineering Society of China. and Chemical Industry Press. All rights reserved.