Electric universal service aims to improve the individual living quality in remote and underdeveloped areas, the implementation of which can promote the sustainable development of people’s lives and the local economy to some extent. A social welfare evaluation model of electric universal service was proposed, which was divided into economic and non-economic welfare evaluation models. After the factors influencing the social welfare sense of electric universal service were identified from the perspective of sustainability, the economic welfare evaluation model was built based on Atkinson’s social welfare function, and the non-economic welfare evaluation model was constructed based on the ideological connotation of prospect theory. Taking Yunnan province in China as the example, a social welfare evaluation of electric universal service was performed. The result shows that the social welfare of electric universal service for Yunnan rural areas has increased by 9.79% from 2006 to 2011, and the “electric service realization degree” is the most sensitive indicator.