Plastic is one of the most basic materials for many industries. Enterprise, as an important stakeholder in plastic pollution control, still lack methodology for investigating the performance of mitigating its plastic pollution. In this work, we proposed a methodology, integrating material flow analysis, life cycle analysis, and scenario analysis for analyzing plastic footprint (incl., material and environmental footprint) at enterprise level and from the perspective of supply chain. A clothing enterprise was chosen as the studied case, and three pathways of plastic reduction were analyzed, incl., reducing unnecessary plastic packaging, using alternative materials, and using recycled materials. The indexes of the plastic footprint of the case enterprise were obtained. In 2019, the weight of plastic packaging used by the case enterprise was 1,949.10 t. The average weight of plastic packaging used for each garment was 19.67 g. The weight of plastic packaging consumed per 10,000 USD of revenue was 0.25 kg. It was found that promoting lightweight plastic materials in supply chain (~14% reduction in thickness of plastic packaging bags), reducing unnecessary plastic use within the enterprise, increasing the number of plastic packaging cycles (~50% reused), and using recycled plastic materials (~15%) are effective ways for enterprises to achieve environmental benefits.