Based on data from 30 provinces in China, this paper builds a coordination degree model and a coupling coordination degree model (CCDM) for a carbon emission-urbanization system (CUS) that explores how to achieve low-carbon development during a rapid urbanization phase. Scenario analyses and case study were applied to illustrate the results, which show five basic conclusions. 1) Low-carbon development doesn't require eliminating energy consumption completely during urbanization 2) The average level of urbanization is relatively low owing to the large disparities among provinces and the provinces' economic development. Though the development of low-carbon in the 30 provinces is generally rapid, the gap between the highest provinces and the lowest provinces is relatively large because of their different socio-economic features. 3) Much more attention should be paid to CO2emissions per capita. The quality of public social service, the basic and medical insurance coverage for the elderly, the community service coverage in infrastructure and the green design during urban construction should be improved. 4) The coordination of CUS is closely related to the different development stages and geographic locations of each province. 5) For different types of provinces with different degrees of coupling coordination,there is a need to explore different development directions.