The third Plenary Session of the 20th CPC Central Committee clearly stated that,regional cooperative legislation should be explored.Regional cooperative legislation is an important institutional innovation for the in-depth implementation of the strategy of coordinated regional development in the new era. Although the text of the Constitution does not explicitly use the concept of regional cooperative legislation, the obligation of the state to guarantee coordinated regional development, as interpreted in its preamble and general programme, can provide a constitutional basis for regional cooperative legislation. Central legislation has responded to the needs of practice timely, with amendments to the Organic Law of Local People’s Congresses and Local People’s Governments in 2022 and to the Legislation Law in 2023, which added relevant provisions and provided a general legality basis for regional cooperative legislation. A large number of policy documents, as well as the practical need for high-quality and efficient handling of cross-regional affairs, have also provided sufficient basis for the practice of regional cooperative legislation. The theoretical basis of regional cooperative legislation has been proved in the dimensions of constitutionality, legality, compatibility with policy and factuality. In practice, regional cooperative legislation by local people’s congresses not only fully exploit the innovation potential of local legislation, but also inevitably face a real dilemma in the case of insufficient operational legal basis, faced with insufficient modelling, understanding bias of cooperation, and insufficient rigidity in the effectiveness of legislative achievements. The reasons lie mainly in the unequal substantive status of local people’s congresses, insufficient public participation in the legislative process, and imperfect mechanisms for cooperative legislation. And the essential reason lies in the game of interests. It is necessary to break the traditional regional and hierarchical concepts by introducing the perspective of new regionalism, to promote the formation of a mutually beneficial relationship model between localities on the basis of cooperation, to establish a regional view of overall interests in regional cooperative legislation, and to seek a legislation consensus beyond local interests. On the basis of conceptual optimization, rational negotiation is used as the basic method to weigh the interests of local people’s congresses. The deepening of public participation is taken as a priority, and the multi-level participation of the public in regional cooperative legislation is strengthened in terms of public participation awareness, participation capacity, participation mode and participation degree, so as to seek the greatest common denominator among the interests of various subjects and effectively solve regional public problems. At the mechanism level, it seeks to improve the overall systematic improvement of the operation mechanism and safeguard mechanism. In the operation mechanism, the process should be clearly defined, and cooperation should be reflected in all process of the legislation, so as to prevent it from being reduced to a mere formality. In the safeguard mechanism, through optimizing the multi-level joint meeting system, setting up a regular information exchange platform, exploring the establishment of a compensation mechanism for benefits, and linking up the performance assessment mechanism, safeguards have been provided to ensure the function of regional cooperative legislation.