In this work, a novel C/Bi/Bi2O3 composite photocatalyst was prepared by a facile one-pot method, using EDTA-Bi as a precursor. The C/Bi/Bi2O3 composite photocatalyst exhibited higher photocatalytic activity than Bi2O3 on the degradation of 2,4-dichlorophenol (2,4-DCP) under both simulated sunlight and visible light irradiation. Metallic Bi and the remaining organic carbon cannot only enhance the absorption of lights, but also accelerate the seperation of photogenerated charge carriers. As a result, the photocatalytic activity is enhanced. More importantly, this paper provides a facile method for the preparation of C/Bi/Bi2O3 composite materials, which is suitable for mass production.