Abstract: The public welfare nature for all is one of the core concepts of China’s national park system, and its realization under the rule of law constitutes a key issue for the construction of ecological civilization and the improvement of the protected area system. Adopting normative analysis as the primary method and empirical analysis as the supplement, combined with the paradigm of comparative law research, this paper integrates the theories of ecological justice, environmental rights, and sustainable development with the particularities of national parks, including trans-regional distribution, ecological sensitivity and the intertwining of multiple stakeholders. Based on the practical context of the National Park Law of the People’s Republic of China, this paper analyzes the practical dilemmas regarding public participation and legal liability norms in realizing the public welfare nature of all national parks in China. Drawing on typical domestic practical cases and the rule of law experiences of countries such as the United States, the Republic of Korea, the United Kingdom, and Canada, the paper points out several issues in the current system. These include overly general provisions and unbalanced guarantees for public participation, a lack of preventive regulation, ambiguous liability for ecological environment restoration, the absence of punitive damages, and unclear procedures for civil public interest litigation. On this basis, this paper proposes optimization approaches from the dual-core perspectives of public participation and liability regulation. On the one hand, it optimizes the provisions on public participation by refining the boundaries of participation rights, establishing a cross-regional collaborative participation mechanism, and strengthening the preferential participation rights of indigenous residents and the accountability mechanism. On the other hand, the legal liability system must be perfected by strengthening preventive liability regulation, improving ecological restoration liability clauses with the orientation of "restoration priority," and establishing the punitive damages system and dual supervision system, so as to provide a solid legal guarantee for realizing the public welfare nature of all national parks.