Abstract: The recycled polyester filaments prepared from recycled polyethylene terephthalate (PET) bottles and virgin filaments prepared from refined terephthalic acid and ethylene glycol were used as the analysis objects. The whole life cycle assessment (LCA) method was used to quantitatively analyze the environmental impact and contribution of each stage of production, and some suggestions for reducing environmental impact were put forward. Five environmental impact categories, including global warming potential (GWP), acidification, abiotic depletions, photochemical oxidation and terrestrial ecotoxicity, were selected for classification and calculation. The results showed that the environmental impact contribution of melt spinning stage in the production process of recycled filament was greater than that of physical treatment stage. Through characterization analysis and normalization analysis, compared with the virgin filament, the global warming potential of recycled filament per 100 kg was reduced by 32.09 kg CO₂ eq, and the acidification potential was reduced by 0.37 kg SO₂ eq. The most important categories of environmental impact in the production of virgin filament and recycled filament were abiotic depletions. According to the comprehensive and intuitive assessment of five environmental impact categories by the life cycle polygon method, the environmental impact of recycled filament was smaller than that of virgin filament, and the environmental impact could be reduced from the aspects of energy optimization and process improvement.