In this paper, the Cl-doped hollow microspherical Bi2WO6 nano-photocatalyst was self-assembly synthesized creatively by one-step solvothermal method using the surface charge regulation strategy for electrostatic adsorption effect of anion in KCl and cation in polyvinylpyrrolidone (PVP). The crystal structure, morphology, element distribution, chemical state, and optical characteristic were, respectively, characterized. The reasons for improving the photocatalytic activity were investigated by degrading tetracycline hydrochloride (TCH). Combined with characterization analysis and the density functional theory (DFT theory), the "double-effect modification" mode under the surface charge control strategy can not only successfully dope the Cl- to achieve functionalization of the product, but also achieve effective control of the product morphology through electrostatic self-assembly process. The electron hole pair recombination was further inhibited, and the photocatalytic activity was improved. The proposed mode provides a simpler, more efficient and widely applicable method for the modification of Bi2WO6 to enhance its photocatalytic activity.