In this study, a [email protected] nanocomposite was synthesized by chemical deposition of Ag nanoparticles onto graphene oxide (GO) through a hydro thermal reaction, and doxorubicin (DOX), one of the most effective drugs against a wide range of cancers, was employed as the model drug and linked to [email protected] via ester bonds with a very high drug loading efficiency (∼82.0%, weight ratio of DOX/[email protected]), then [email protected] was functionalized by DSPE-PEG2000-NGR, giving [email protected] with active tumor-targeting capacity and excellent stability in physiological solutions. The release profiles of DOX from [email protected] showed strong dependences on near-infrared (NIR) laser and the SPR effect of Ag nanoparticles. Compared with free DOX in an in vivo murine tumor model, [email protected] afforded much higher antitumor efficacy without obvious toxic effects to normal organs owing to 8.4-fold higher DOX uptake of tumor and 1.7-fold higher DOX released in tumor with NIR laser than the other tissues. Besides, in this work, [email protected] not only served as a powerful tumor diagnostic X-ray contrast agent, but also as a strong agent for photothermal ablation of tumor, the ability of [email protected] nanoparticles to combine the local specific chemotherapy with external photothermal therapy (PTT) significantly improved the therapeutic efficacy. [email protected] showed excellent chem-photothermal therapeutic efficacy, tumor-targeting property, NIR laser-controlled drug releasing function and X-ray imaging ability, demonstrating that there is a great potential of [email protected] for cancer diagnosis and therapy.