China has entered a new era of high-quality urban development. As an important stock resource in the city, old industrial parks face new situations of transformation and regeneration due to various problems such as chaotic land layout, low industrial efficiency, and lack of supporting facilities. However, existing research primarily focuses on case studies in large cities and rural areas, lacking fine-tuned adjustment plans for county-level cities in China. Therefore, this article aims to establish a decision-making and evaluation framework applicable to economically underdeveloped areas, providing a reference for the transformation of inefficient industrial land in county-level cities nationwide. Based on expert consultation, case studies, and other methods, a low-efficiency land evaluation model is constructed from three dimensions: spatial efficiency, operational efficiency, and industry screening, to tap the potential value of stock land. The research data are primarily provided by government departments and processed and quantified using GIS software. Based on the quantitative evaluation results of the Shengfang Industrial Park in Lianhua County, Jiangxi Province, three major strategic directions for land parcels with different renewal potentials are proposed: retention and improvement, rectification and renewal, and redevelopment and utilization. Targeted renewal strategies for the case industrial park are proposed from the aspects of spatial renewal and implementation mode guidance. The results of this study could provide suggestions for local government decision-making, which could contribute to the improvement of resource utilization efficiency and economic benefits. The findings could also provide references for the planning and development of industrial parks in other impoverished counties. Future research could focus on long-term monitoring, stakeholder engagement, and the application of evaluation results.