The sustainable development is a key issue in the whole field of economy, culture and society, which can be accomplished by the improvement of environment. Recently, life cycle assessment(LCA) has been applied to reduce environmental impacts preliminarily by evaluating the environmental performance of a product through its life cycle. In this study, life cycle assessment was performed to analyze quantitatively the environmental impact on the interior panel of electric motor unit(EMU). As a result, the interior panel with aluminum showed the most global warming(GW), while that with phenol and plastic showed high fresh water aquatic ecotoxicity(FAET) and marine water aquatic ecotoxicity(MAET), respectively. Global warming was occurred mainly due to the emission of $CO_2$ by energy consumption. FAET and MAET were caused by the pollutants released from acid-washing and paints coating process. Therefore, an environmental-friendly EMU can be designed considering the environmental impacts of interior panel.