BiVO4/PDA(Polydopainine)/g-C3N4 was synthesized by facile ultrasonic dispersion and self-assembly at the room temperature, and monoclinic BiVO4 was embedded on PDA/g-C3N4 sheet, which PDA was first formed in situ on the surface of g-C3N4 via self-polymerization of dopamine. The dependence of photocatalytic activity on the structural, electronic and optical properties of the BiVO4/PDA/g-C3N4 nanostructure has been explored using XRD, XPS, TEM, SEM, DRS, PL, BET and photocurrent. The BiVO4/PDA/g-C3N4 photocatalysts show higher activity of glyphosate degradation than BiVO4, g-C3N4 and BiVO4/g-C3N4 under visible light irradiation. The enhanced activity of BiVO4/PDA/g-C3N4 can be significantly attributed to the improved visible light absorption, enhanced specific surface area and increased charge separation. PDA has a strong and irreversible binding ability onto BiVO4 and g-C3N4 to form BiVO4/PDA/g-C3N4. This simple method at the room temperature is promising for the synthesis of high performance composite photocatalysts for different applications, such as pollutant degradation, photocatalytic splitting water, etc.