Quantitative assessments of progress towards Sustainable Development Goals (SDGs) and the complex interactions of indicators are critical for monitoring the achievement of SDGs and guiding policymaking and implementation. Based on Big Earth Data and the SDGs global indicator framework, an index system for evaluating progress towards SDGs in frontier, multi-ethnic underdeveloped areas was developed from the perspective of social, economic, and environmental dimensions and included 70 indicators. The study area was the National Innovation Demonstration Zone (Lincang) for the 2030 Agenda for Sustainable Development. The model incorporated regional characteristics and data acquisitioned from Lincang in 2015-2020 through field research. Consequently, we calculated the social, economic, and environmental sub-indices and integrated index of sustainable development of Lincang City from 2015 to 2020, evaluated the progress trend of SDGs and indicators, and proposed key challenges and solutions for the sustainable development of Lincang City. Research shows that the integrated index and the social, economic, and environmental sub-indices of sustainable development have shown an increasing trend from 2015 to 2020. In terms of the SDGs, progress was achieved with respect to all 16 SDGs. The average annual growth rate of SDG 5 was the highest, whereas that of SDG 13 remained unchanged. In addition, 81% of indicators showed acceptable progress. This study provides a reference for sustainable development planning in other typical demonstration areas and underdeveloped mountainous areas in China and worldwide.