Environmental security is an integral part of the global security agenda. The COVID-19 pandemic and the economic recession in many countries have resulted in complicated impacts on global environmental security ad governance. At the macro level，this article presents a preliminary attempt to analyze the short-and long-term trend of global challenges to environmental security，and the features of the measures taken by the global governance system. First，it discusses the concept of global environmental security from the perspectives of the direct and indirect influences of environmental problems. Second，referring to the practice of the international community since 1970s，it explores the general responses of the global governance system from three perspectives—governance structure，agenda setting，and resource allocation. On this basis，and considering the impacts of the COVID-19 pandemic on world economy and environmental security challenges，it uses four major international organizations as examples to analyze the features of the measures that the global governance system has taken. Those features include the further fragmentation of governance structure，over-concentration on short-term agendas，and unbalanced allocation of resources. Its conclusion argues that by focusing on a few global environmental security issues relevant to COVID-19，major international organizations have been contributing to address the current challenges，but without sufficiently taking into account the mid-and long-term features of global environmental security—especially the needs of developing countries. Therefore，developing countries would not only need to put more emphasis on systematically tackling global environmental security challenges，but also need to improve the way in which the global governance system addresses environmental security challenges by strengthening the interactions between international environmental agreements，e.g. the Convention on Biodiversity，and major international organizations.