In order to make long-lived photoexcited charges for efficient catalytic photodegradation, rare earth elements are often incorporated into semiconductors. We studied the doping effect on photodegradation efficiency of Bi2WO6 samples with europium ions which were successfully synthesized by a simple one-step. The prepared catalyst was characterized by multiple techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activities of pristine Bi2WO6 and xEu-Bi2WO6 (x=1, 2, 3, and 4) were investigated in the presence of H2O2 for 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T) as a target contaminant under visible light irradiation. The incorporation of Eu3+ into Bi2WO6 where Eu3+ ion played the role of an electron acceptor was favorable for transferring photoinduced electrons from Bi2WO6 to Eu3+, thereby increasing separation efficiency of photoinduced electron-hole, leading to enhanced photocatalytic activity of xEu-Bi2WO6. Under optimized condition, the photodegradation efficiency of 2,4,5-T by 2Eu-Bi2WO6 samples was 1.7-fold higher than that of pristine Bi2WO6 sample. We demonstrate that Eu3+ ion is a promising candidate for the development of a visible-light active semiconductor catalyst for environmental remediation.