Prostate cancer (PCa) routinely employs magnetic resonance (MR) imaging, while metastatic PCa needs more complicated detection methods for precise localization. The inconvenience of using different methods to detect PCa and its metastases in patients and the limitations of single-mode imaging have brought great challenges to clinicians. Meanwhile, clinical treatments for metastatic PCa are still limited. Herein, we report a targeted theranostic platform of Au/Mn nanodots-luteinising hormone releasing hormone (AMNDs-LHRH) nano-system for multi-mode imaging guided photothermal therapy of PCa. The nano-system not only can simultaneously target Gonadotropin-Releasing Hormone Receptor (GnRH-R) positive PCa and its metastases for accurate preoperative CT/MR diagnosis, but also possesses fluorescence (FL) visualization navigated surgery, demonstrating its potential application in clinical cancer detection and surgery guidance. Meanwhile, the AMNDs-LHRH with promising targeting and photothermal conversion ability significantly improve the photothermal therapy effect of metastatic PCa. The AMNDs-LHRH nano-system guarantees the diagnostic accuracy and enhanced therapeutic effect, which provides a promising platform for clinical diagnosis and treatment of metastatic PCa. STATEMENT OF SIGNIFICANCE: Accurate clinical diagnosis and treatment of prostate cancer and its metastases is challenging. A targeted theranostic platform of AMNDs-LHRH nano-system for multi-mode imaging (FL/CT/MR) guided photothermal therapy of metastatic prostate cancer has been reported. The nano-system not only can simultaneously target prostate cancer and its metastases for accurate preoperative CT/MR diagnosis, but also possesses fluorescence visualization navigated surgery, demonstrating its potential application in clinical cancer detection and surgery guidance. The nano-system with great targeting and photothermal conversion ability significantly improve the photothermal therapy effect of metastatic prostate cancer. Overall, the AMNDs-LHRH nano-system integrates tumor targeting, multi-mode imaging and enhanced therapeutic effect, which can provide an effective strategy for the clinical diagnosis and treatment of metastatic PCa.