The sustainability assessment of natural capital (SANC) is one of the key elements in the field of national park protection. Assessing the impact of socioeconomic development on the Shennongjia National Park Pilot (SNPP), a typical national park in China, would be extremely conducive to the sustainable management of its natural capital. To this end, a natural capital account system encompassing transportation, accommodation, food, and waste for both locals and tourists was developed. Throughout the period from 2007 to 2016, a SANC was conducted in SNPP based on the 3D ecological footprint (EF 3D ) model to measure stock consumption as well as flow occupancy. The main conclusions were as follows: First, the ecological footprint (EF) size of the SNPP increased yearly from 2007 to 2014, although it decreased in 2015, when the government started preparing for the SNPP. Second, rapid tourism-related developments brought about an increase in the EF of built-up land, and the increasing medicinal planting also enlarged the EF of arable land. Third, the cumulative EF of tourism was 2.82 times that of locals over the past decade. This gap has been expanding. Overall, the results show relatively steady sustainability in terms of natural capital in the SNPP. More precisely, the preceding stock consumption did not severely constrain the function of the current regeneration of flow capital, whereas tourism and planting have become potential threats to the sustainability of the natural capital.Sustainability 2019, 11, 956 2 of 17 destruction of animal habitats due to the results of recreational activities, such as garbage, local natural resource consumption by agricultural production [2], reduced national park space due to hotels and recreation trails [3], and soil erosion caused by traffic [4]. Unsustainable natural capital utilization is causing natural capital to be an increasingly limiting factor for human well-being in the Anthropocene era [5,6].Natural capital, the most fundamental of the forms of capital, sets the ecological limits for our socioeconomic systems [7]. Environment and development economics theory states that maintaining natural capital is the corner-stone of sustainable development [8]. However, the significance of natural capital used to be overlooked when making decisions. Consequently, the sustainability assessment of natural capital (SANC) provides insights into designing environmental policy and sustainable development planning. At present, the SANC does not have a mature evaluation system that can directly interface with economic development. Hence, studies on natural capital mainly adopt ecological footprint (EF) [9], ecosystem service valuation [10], energy theory [11], net primary productivity [12], life cycle assessment [13], etc. Currently, the SANC generally relies on various EF methods [14][15][16][17]. These methods can clearly quantify human occupation and the supply of natural capital, which are more operative and less subjective for the SANC.The EF model is a mature approach for quantitativ...