With the global attention on plastic pollution, polylactic acid (PLA) is quickly becoming an alternative to traditional plastics. The current pressing challenge now is to enhance the degradation rate of PLA while simultaneously reducing costs. We investigated the influence of reed fibers on the biodegradation of PLA-based composites under various environmental conditions. The crystallization behavior, surface morphology, and functional group changes of the samples during enzymatic degradation were analyzed using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Fourier transform infrared spectrometer (FTIR). The results indicate that reed fibers significantly increased the hydrophilicity of the composites and reduced the crystallinity of PLA, thereby enhancing the degradation rate of the composites. This rate increased with the higher concentration of reed fibers. The research results will provide a theoretical reference for the design of PLA composites that are better aligned with market demand, which is used to balance the requirements for degradation performance during product use and after disposal and expand the application of PLA/RF composites in the construction, agriculture, and packaging. © 2024 Walter de Gruyter GmbH, Berlin/Boston.