Synergistic treatment provides many advantages such as high efficiency and low risk of recurrence compared to single mode of therapy, while the current adoption of therapeutic agents have been greatly stifled by unresolved concerns including poor drug loading capacity and dissatisfactory therapeutic effect. Here we proposed and fabricated a multifunctional nanotheranostic agent, which consists of PEGylated and DOX-loaded bismuth tungstate nanosheets (abbreviated as Bi2WO6-DOX-PEG NSs). The Bi2WO6 NSs not only possess excellent drug loading capacity (81.3 wt%), but also can generate reactive oxygen species (ROS) and high hyperthermia effect (36.5% heat transfer coefficient) when irradiated by high penetrated near-infrared (NIR) light with low power density (0.5 W cm(-2)). The in vitro and in vivo experiments show that the Bi2WO6-DOX-PEG NSs have negligible systemic toxicity, good photostability, and excellent computer tomography (CT) imaging effect. In vivo results also exhibit obviously higher tumor ablation performance of Bi2WO6-DOX-PEG than any single-modal therapy, which is derived from NIR laser triggered synergistic effect. As the first demonstration of Bi2WO6 NSs as phototherapy agent, our finding may pave the way for the application of this kind of two-dimensional (2D) nanomaterials in biomedical field.