Under the background of "dual-carbon" target, cities as the important subjects of low-carbon strategy implementation, have introduced many challenges. In order to help the sustainable development of urban ecology, the evaluation index system was constructed, the data was qualified and the reliability and validity were analyzed, PCA algorithm was used to degrade the data and extract the features, and the key influencing factors were determined by interpreting and analyzing the weights of the principal components. The result shows that the key factors affecting the construction of low-carbon cities are grouped into eight categories, including environment, energy and buildings, with a total of 11 indicators. Accordingly, the optimal path and feasible strategies for the construction of low-carbon cities are explored to promote the construction of "dual-carbon" goals.