CeO2 with X-architecture was synthesized using the hydrothermal route assisted by polyvinyl pyrrolidone, and employed to investigate the degradation of methylene blue under UV-light irradiation. The as-obtained CeO2 sample exhibited higher photocatalytic activity than traditional CeO2 sample prepared by precipitation route due to its irregular X-architecture shape with clear boundary and micro/mesopore surface structure. The novel X-architecture shape of CeO2 facilitates the efficient photo-generated charge transfer and separation under UV-light irradiation, leading to the superior stability for the photo-degradation of methylene blue.