An α-Fe2O3-TiO2/fly ash cenospheres (FAC) composite photocatalyst was prepared by depositing α-Fe2O3 onto floating TiO2/FAC, which was synthesized via a simple sol-gel method. Scanning electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, and UV-vis diffuse reflectance spectroscopy were used to determine the structure and optical property of α-Fe2O3-TiO2/FAC. Rhodamine B was selected as the model substance for photocatalytic reactions to evaluate catalytic ability. Results showed that the degradation efficiency was close to 100% within 1h. Active species measurements indicated that OH served as the dominating active species that played a key function in the reaction. A possible photocatalytic degradation mechanism of α-Fe2O3-TiO2/FAC was also discussed based on experimental results.