Abstract: The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Convention on the Conservation of Migratory Species of Wild Animals (CMS) are two international treaties with species conservation as their core objective. Both adopt appendix-listing mechanisms to categorize, and regulate species of conservation concern. Based on a comprehensive review of the two conventions and their appendix systems, this paper analyzes the differences in animal species listed in the appendices and puts forward targeted implementation suggestions. The findings reveal marked divergences between the two conventions in taxonomic coverage, conservation priorities, and species composition. As of March 23 2026, CITES appendices include 6 689 animal species or subspecies, while CMS appendices cover 1 205. The CMS listing is taxonomically confined to mammals, birds, reptiles, fish, and insects, with only one insect species listed. In contrast, CITES encompasses a broader taxonomic scope, additionally including amphibians, corals, and other invertebrates. A total of 369 animal species or subspecies are listed under both conventions, predominantly distributed across Carnivora, Cetacea, Artiodactyla, Falconiformes and other taxa. Most cross-listed species share identical appendix levels under the two conventions. Overall, the species listings of the two conventions exhibit a pattern of predominance complementarity with limited overlap, jointly contributing to a global conservation framework for endangered fauna. To enhance future synergy, it is recommended to harmonize the taxonomic and nomenclatural systems between CITES and CMS, promote the development of a joint CMS-CITES species database, strengthen coordination with other relevant multilateral environmental agreements, and continuously monitor the implementation progress of CMS. These measures would facilitate the comprehensive conservation of global biodiversity.