Abstract: ²²⁵Ac with the advantages of longer half-life(10 d), shorter range(<100 μm) and high energy deposition(80-100 keV/μm) compared with other medical isotopes, is one of the most important alpha-emitting nuclides. The α particles emitted by ²²⁵Ac can cause DNA double-strand breaks in tumor cells, which is more favourable in clinical application. This review delineates the decay characteristics and production methodologies of ²²⁵Ac, alongside detailing the conjugation of ²²⁵Ac with target-specific ligands through various chelation strategies. It encapsulates the advancements in research and clinical applications of ²²⁵Ac-labeled compounds, including ²²⁵Ac-prostate-specific membrane antigen(PSMA)-617, ²²⁵Ac-PSMA-I&T, ²²⁵Ac-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid(DOTA)-SP, and ²²⁵Ac-1,4,7,10-tetraazacyclododecane-N, N', N″, N'″-tetraacetic acid d-phenylalanine1-tyrosine3-octreotide(DOTATE), in the therapeutic regimes for prostate cancer, gliomas, breast carcinoma, and pulmonary malignancies. The difficulties and challenges of ²²⁵Ac-labelled radiopharmaceutical are also forecasted, in order to provide reference for the research and application of ²²⁵Ac-labelled radiopharmaceuticals in the treatment of malignant tumors.