Bi2WO6 is a widely used photocatalyst, which has a good visible light response owing to the narrow band gap. But in the process of photocatalytic reactions, the combination of electrons and holes has a significant effect on the photocatalytic activity. In this work, I-doped Bi2WO6 microflowers were prepared by a simple one-step hydrothermal method. The microflower has a large surface area, which can be conducive to the adsorption of pollutants, degrading Rhodamine B and removal of NO effectively. The structure, as well as optical properties of the I-doped Bi2WO6 microflowers have been characterized by a series of techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM), and UV-vis diffuse reflectance spectroscopy. According to the results of UV-vis spectra, the I-doped Bi2WO6 microflowers are found demonstrating a significantly enhanced visible light absorption. The photocurrent and photoluminescence spectra indicate an increased separation rate for the I-doped Bi2WO6 photocatalyst of the photo-generated electron-hole pairs. Under visible-light irradiation, the S3 I-doped Bi2WO6 photocatalyst shows the photocatalytic efficiency about 97.6% and 50.0% for Rhodamine B and NO, respectively.