Abstract: Gastrin-releasing peptide receptor (GRPR) is highly expressed in prostate cancer, breast cancer, and gastrointestinal tumors, but lowly expressed in normal tissues and organs, providing an ideal target for molecular imaging. Existing research has fully validated its biological basis and clinical value, but the core of truly driving clinical translation lies in the continuous optimization of its molecular structure. This article reviews the development and evolution of GRPR-targeting molecular probes: the shift from early agonists to antagonists has significantly improved metabolic stability and imaging contrast; simultaneously, strategies such as peptide modification, dimer design, linker arm regulation, chelator matching, and radionuclide selection have further enhanced tumor uptake and image quality. In the future, multi-target molecular design, therapeutic integration, and patient-stratified personalized applications will become important directions for enhancing the clinical value of GRPR-targeted imaging.