With the rapid development of cities, urban transportation has been swift growth, yet the quality of the urban transportation environment has seriously declined. According to the requirements of sustainable development of urban transportation, the traffic environmental carrying capacity (TECC) is taken as a quantitative indicator to measure the sustainable development of urban transportation. In this paper, an appropriate evaluation indicator system is established from the aspects of traffic environmental resource carrying capacity and traffic environmental pollution carrying capacity. It combines the extensible model and the entropy weighting method (EWM) to construct a comprehensive evaluation model for traffic environmental carrying capacity, achieving a thorough evaluation of the level of traffic environmental carrying capacity. Finally, taking Qingdao as an example, this paper evaluates the level of urban traffic environmental carrying capacity from 2013 to 2022, and puts forward suggestions on the management of sustainable transportation development in Qingdao based on the evaluation results and traffic status, providing the scientific basis for realizing sustainable development of urban transportation.