To address the medical challenges posed by glioblastoma, a novel and high-performance tumor inhibitor (La@FA-CDs) composed of folic acid and lanthanum nitrate hexahydrate, was successfully synthesized and demonstrated effectiveness in inhibiting the growth of U251 and LN299 cells. The microstructure of La@FA-CDs was extensively analyzed by FTIR, UV-Vis, XPS, TEM, AFM NMR, and nanoparticle size analyzer. The optical and electrical properties of La@FA-CDs were characterized using a fluorescence spectrometer and a zeta potential analyzer. Biological assays, including the CCK8 proliferation assay, scratch assay, flow cytometry, cytoskeleton staining, and live/dead staining were conducted to assess antitumor properties and cytotoxicity. The result revealed that the La