National park development is a critical component for advancing ecological civilization in China, aligning with the nation’s commitment to sustainable development and environmental stewardship. Local communities are among key stakeholders of national park development, as their livelihoods are significantly influenced by ecological protection and tourism development initiatives. Moreover, their attitudes and perceptions toward conservation and development would directly impact the sustainable development of national parks. Therefore, harmonizing ecological conservation and tourism to foster sustainable community development is central to establishing a national park model with Chinese characteristics. Responding to the above research need on sustainable community development in China’s national park development, this study employs the sustainable livelihood framework to assess the impacts of ecological protection and tourism on the traditional livelihood systems in Qilian Mountain National Park. Taking Nannigou Village in Tianzhu County as a case study, we engaged a mixed method research approach through quantitative household questionnaires and qualitative semi-structured interviews with key stakeholders. Major research findings include that: (1) Ecological protection and tourism development in the Qilian Mountain National Park Pilot Area have shifted local livelihoods from traditional animal husbandry to a more diversified mix, including labor migration, tourism, and ecological patrol work. This transition has enhanced community livelihood sustainability to some extent. (2) It has been recognized that Qilian Mountain National Park development has improved ecological conditions, conserved local biodiversity, and raised environmental awareness among the residents. However, conservation measures have also restricted traditional livelihoods of local residents, particularly for animal husbandry. Such transition pressures the local community to seek alternative livelihood strategies, including tourism related livelihoods. Emerging challenges are identified to include spatial imbalances in ecological protection policies and the increase in human-wildlife conflicts. (3) Tourism has promoted livelihood diversification and economic growth, with strong participation willingness among community members. Yet, uneven distribution of benefits, limited integration with traditional industries, and negative environmental and socio-cultural impacts remain concerns. Drawing on these findings, specific practical suggestions are proposed to enhance community capacity through skills training and inclusive engagement mechanisms, optimize tourism’s regional economic benefits while mitigating disparities in community participation, and impose continuous monitoring of conservation and development strategies to minimize adverse socio-ecological impacts. With the case study in Qilian Mountain National Park Pilot Area, this study enriches the theoretical verification and empirical analysis of the sustainable livelihood framework on communities in the national park context in China. It is of theoretical and practical significance for balancing the conservation and development of national parks in China and would provide references for protected areas in other parts of the world.