The ecologicalization of industrial parks and the construction of eco-industrial parks (EIPs) are new trends within industrial clusters. However, land use changes and the related losses of ecosystem services are often neglected in ecological evaluations of industrial parks. This negligence is particularly significant in developing countries such as China, where the economic outputs of land use have significantly improved, but a considerable number of farms and forests have been exposed to industrial land, which greatly reduces the regional natural capital. This article proposes a set of eco-efficiency indicators for evaluating the ecological performance of an industrial park from the perspective of the ecosystem services or natural capital reflected by such services. A corresponding efficiency evaluation model and index system was constructed and used in a case study of Ningguo Gangkou industrial park in eastern China. Based on a comparative analysis of the eco-efficiency of the Gangkou industrial park in 2007 and 2015, we found that although the total ecosystem service value (ESV) of Gangkou in 2015 had increased by 27% compared with that of 2007, the maintenance of the ecological regulating and supporting services of the park had declined, and the indirect economic value of these services had decreased by 14%. Because of the development of the park over the last 10 years, the different ecosystems and the relevant ecosystem services had undergone different degrees of changes. The main task of this study was to establish an ESV-based eco-efficiency evaluation index system that can be used by decision makers for sustainable landscape planning and development.