To promote the realization of EU Green Deal, the European Council initiated the Carbon Border Adjustment Mechanism, which laid restrictions for importers to declare the carbon emission of the goods so as to purchase certificate for the extra carbon emission pursuant to EU regulations. With respect to the current version of Carbon Border Adjustment Mechanism, it constitutes discrimination against like product from non-EU member countries, thus violating national treatment and most favored nation treatment. However, Carbon Border Adjustment Mechanism can protect the security of lives of human, animals and plants as well as exhaustible natural resources. It does not constitute arbitral discrimination and disguised restriction on international trade. Consequently, EU could resort to environment exceptions to justify Carbon Border Adjustment Mechanism. Under such a circumstance, China should stick to multilateralism, improve the carbon emission trading system, develop low-carbon technology and enhance the ability to relevant lawsuits.