Abstract: The purpose of establishing national parks is to protect the authenticity and integrity of natural ecosystems, which objectively requires a unified management system, leading to increasingly prominent importance of synergistic legislation. Based on the concept, characteristics and commonality discussions of trans-provincial national parks, this paper summarizes the practical progress, existing problems and normative basis of synergistic legislation in these parks, analyses the dilemmas encountered by them and proposes corresponding countermeasures. The research concludes that the successful practice of synergistic legislation for the Giant Panda National Park and Wuyi Mountain National Park represents an innovation of trans-provincial synergistic legislation for national park management, where some issues still need to be improved. The synergistic legislation in trans-provincial national parks faces many challenges, which are primarily manifested in the difficulty of harmonizing legislative standards, unclear trans-regional legislative procedures, plurality of legislative demands, difficulties in implementing and monitoring legislation, and additional legislative costs. Hence, it is necessary to establish a sound legal system for synergistic legislation, further standardize its working mechanism, establish a coordination system for trans-provincial national parks, improve the implementation and monitoring mechanisms for synergistic legislation, and strengthen its cost-sharing system.