[Objective] To reserch the vulnerability of urban water resources, and reveal the ability of the sustainable development of urban water resources in order to provide reference for building sustainable cities.[Methods] This article listed the water resources of 21 administrative cities of Guangdong Province and Shunde District of Foshan City as empirical subjects. The evaluation index system was established from three perspectives including natural, human and bearing capacity factors. Based on the entropy weight method, the water resources vulnerability assessment model was constructed using the linear weighted summation method.[Results] Water resources in Guangdong Province were relatively vulnerable, and the water resources in Shenzhen City were not vulnerable. Among 22 research subjects, water resource vulnerability of Shenzhen City was most stable.[Conclusion] According to the results of water resources vulnerability assessment in Guangdong Province, and sustainable development of smart city, water resources vulnerability in Guangdong Province was high. The utilization of water resource can be improved through the reform of industrial structure, the construction of smart water affairs and the utilization of science and technology.