It has been a challenging task to develop nontoxic nanoprobes for targeted-imaging and selective therapy of prostate cancer. Herein, fluorescent superparamagnetic nanoparticles with a diameter of 50 nm were conjugated with single-chain Fv antibody against γ-seminoprotein. The resultant nanoprobes showed highly selective targeting, fluorescent imaging, and magnetic resonance imaging. The cytotoxicity effects were investigated on the prostate cancer cells and solid tumors under in vitro alternating magnetic field irradiation. It was found that the as-prepared nanoprobes did not show signs of toxicity within the used maximal dosage. It was also observed that the tumors implanted in nude mice were significantly reduced in size and disappeared gradually due to thermal treatment. The lifespan of post-therapeutic mice loaded with prostate cancer was considerable prolonged. High-performance singlechain Fv antibody against γ-seminoprotein-conjugated fluorescent magnetic nanoparticles may have great potential in applications such early detection and localized thermal therapy of prostate cancer.