In this paper, ultra-thin g-C3N4 nanosheets were prepared by improved ultrasonic stripping method for the first time. Then, g-C3N4 nanosheets were pretreated into Bi+/g-C3N4 nanosheets by electrostatic adsorption principle, and a new type of Cl-Bi2WO6/g-C3N4 heterostructure photocatalyst was prepared by using Bi+/g-C3N4 nanosheets as the substrate. The degradation of RhB under photocatalysis was studied with the compound amount of g-C3N4 and the amount of catalyst by using x-ray diffraction (XRD), a scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy (XPS), Brunauer Emmett-Teller (BET), and ultraviolet visible diffuse (UV-vis DRS) methods on the structure, morphology, and optical characterization charge transfer characteristics, etc. The results of the degradation experiment show that the compound appropriate amount of g-C3N4 can significantly improve the activity of the photocatalyst. At the same time, different amounts of Cl-Bi2WO6/g-C3N4 composite photocatalyst have a significant effect on the degradation performance, and the photocatalytic activity is the best when the input is 2 g/L. Combined with active species capture experiments, a possible degradation mechanism of Cl-Bi2WO6/g-C3N4 Z-type heterostructure photocatalyst was proposed.