Law is dynamic and pluralistic in the dimension of geographical space. In addition，there exists tension of conflict and integration among multiple institutional arrangements. Trans-regional watershed management as a typical multi-institutional arrangement，embodies the spirit of public value and consultation，the rules of space shaping and power allocation，as well as the state of multi-dimensional nesting in harmony with the environment. Therefore，under the hindrance of multi-dimensional governance dilemma，interest conflict obstacle and interregional interaction path，regional collaborative legislation has become the optimal scheme to change the current situation of watershed management. On the basis of joint planning，simultaneous investigation and full consultation，it is an effective way for realize the ecological restoration and comprehensive management of the whole river，that to formulate legislation with identical goals，coherent contents，prominent priorities，distinctive features，coordinated procedures and Shared performance，as well as to establish a specific systems of subject coordination and procedure coordination，information exchange and information sharing，interest balance and benefit compensation，public knowledge and public participation.