Abstract: The fluorescent anti-counterfeiting poly(lactic acid) (PLA) fibers were prepared by melt spinning. The effect of the fluorescent powder mass fraction on the crystalline structure, mechanical properties and fluorescence properties of the fluorescent anti-counterfeiting PLA fibers were characterized by DSC, XRD, fiber strength tester, fluorescence spectroscopy and fluorescence microscopy. Moreover, 3D fluorescence distribution of fluorescent anti-counterfeiting PLA fibers was simulated by using the confocal laser scanning microscopy. Results showed that the emission spectra of fluorescent anti-counterfeiting PLA fibers peaked at 530 nm, indicating the fibers show yellow-green under UV light. With the increasing mass fraction of fluorescent powder, the fluorescence strength of the fibers increased, whereas the tensile strength decreased due to the agglomeration of fluorescent powder. In addition, confocal laser scanning microscopy could be used well to simulate the distribution of fluorescent powder among the fibers.