Sustainability, which involves environmental, social and economic dimensions, is playing an increasingly significant role in product design, of which the environmental dimension is currently the primary focus. Many studies have explored the use of methods or tools, such as life cycle assessment and quality function deployment, to support sustainable product design. However, more studies are needed to explore the associations between product design activities and sustainability, particularly at the conceptual design stage where decisions have high impacts. Therefore, this paper proposes a new approach using taxonomy for sustainable product design concept analysis. It aims to provide new insights for addressing sustainability issues by employing computational techniques, such as natural language processing and ontologies, at early design stages. The approach involves sustainability knowledge capture, knowledge expansion, taxonomy formalisation, and sustainability analysis. A case study has been conducted to demonstrate the workflow of the taxonomy approach and indicate its viability in an education setting.