Assessment of low-carbon development is vital to the sustainable development of urban areas, and is of importance for measures to address global climate change for cities. Based on the concept of low-carbon cities and on previous research, we constructed an indicator system to assess urban low-carbon development. According to this research, a low-carbon city is characterized by reduced urban carbon emissions (including those from economic, social, construction, and transportation sectors). Moreover, some limitations have hindered the improvement of low-carbon development assessment indicator systems. There is no uniform indicator system, making comparisons among domestic and foreign studies difficult. Therefore, there is a need to develop a unified indicator system to assess low-carbon development. In the present study, the indicator system consists of six categories (carbon emission, economic development, social improvement, traffic, and residential and natural environments) and 13 specific indicators:carbon emissions per capita, carbon emissions per unit GDP, GDP per capita, non-agricultural industry share of GDP, expenditure of education as proportion of GDP, urbanization rate, urban construction land area per capita, green coverage, urban civilian car ownership per capita, road area per capita, concentration of sewage treatment plants, safe treatment rate of biological waste, and comprehensive utilization rate of general industrial solid waste. Using data from 35 typical cities in China from 2010 to 2015, the low-carbon development trend of cities was evaluated and analyzed. The indicator system can be applied to a wide range of situations. The results demonstrated that most of the investigated cities showed increasing development of low-carbon economies. Of all investigated cities, Shenzhen had the highest index in both years; low-carbon indices for Hangzhou, Yinchuan, Zhengzhou, Shijiazhuang, and Kunming remained the same; and indices for Chengdu, Changsha, Hefei, and Dalian declined, mainly due to the lack of coordination between urban development and environmental mitigation. Finally, based on the conclusions of this study, the following suggestions for improving the development of low-carbon cities and economies are put forward:(1) The development of a low carbon economy should focus on improving energy efficiency and renewable energy utilization; (2) To improve the urban economic level without increasing environmental impacts, the urban industrial structure should be improved; (3) The development of an urban low-carbon economy is also related to social development, urban construction, traffic conditions, and environmental pollution treatment capacity. In addition to reducing urban carbon emissions and strengthening urban economic development, education, urban greening, land use planning, urban roads, transport systems, and environmental pollution treatment capacities should be improved.