Abstract: With the Northeast China Tiger and Leopard National Park as a case study, this study examines the synergistic path between national park development and the livelihood transformation of local indigenous residents. By focusing on the park′s core conservation areas, it aims to understand how shifts in traditional livelihood practices align with the park′s ecological conservation goals, achieving a win-win situation for biodiversity conservation and local socio-economic development. Through a mixed-methods approach, the study combines structured questionnaires and semi-structured interviews to analyze both quantitative and qualitative aspects of residents′ current livelihoods and experiences. By utilizing the Stimulus-Organism-Response (S-O-R) framework, with national park policies as external stimuli, the study analyzes how they influence residents′ internal perceptions (organism) and subsequently shape their adaptive livelihood behaviors (response). The hypotheses are tested using questionnaire data, verifying the statistical significance of the proposed relationships. There are three core insights. First, there is a significant positive association between residents′ livelihood transformation and the development of national parks. Policies on ecological protection, such as the restrictions on resource extraction and the establishment of protected zones, can promote ecological restoration as well as the diversification of residents′ livelihoods, encouraging a shift from traditional agriculture and livestock rearing toward alternative activities. Second, wildlife conservation provides ecological benefits and creates economic opportunities through eco-tourism, wildlife observation, and related hospitality services. These emerging sectors offer sustainable income sources for residents, support their livelihood transformation, and reduce reliance on traditional production methods that may disrupt conservation objectives. Third, the evolution of livelihood strategies further enhances the positive feedback loop between ecological protection and regional development: As residents engage in livelihood activities compatible with conservation goals, their maintenance of habitats increases community tourism appeal and economic returns, forming a mutually beneficial positive feedback loop. Despite the positive impacts of national park policies, several barriers hinder coordinated development. Residents generally have limited awareness of policies and rate policy support and ecological benefits poorly. More than half of the surveyed households suffer livestock and crop losses due to wildlife, highlighting persistent human-wildlife conflicts. Policy information dissemination predominantly occurs through government channels with insufficient community-level communication, leading to divergent understandings of coordinated development among different groups. Additionally, significant regional economic disparities exist, and the current top-down ecological compensation mechanisms fail to adequately address local needs, resulting in limited economic benefits and low policy satisfaction among residents. The study suggests that optimizing national park policies through coordinated development models by integrating ecological compensation, conflict mitigation, and targeted awarenessraising can better balance ecological conservation objectives with the socioeconomic aspirations of resident communities. Such policy optimizations are crucial for achieving dual objectives of effectively conserving tiger and leopard populations and their habitats, as well as promoting sustainable improvement in local livelihoods, thereby advancing ecological and social sustainability simultaneously.