[Objective] The objective of the research is to study the key factors that influence the water resource carrying capacity in Guiyang City of Guizhou Province in order to provide basis for the sustainable development of water resources and soci-economy in the city. [Methods] Taking Guiyang City as a case study, the water resources system was divided into three subsystems including water resource, ecological environment and soci-economic subsystems. Evaluation indices were selected and multilevel fuzzy comprehensive evaluation model was established. [Results] The result showed that water resources carrying capacity improved continuously from 2003 to 2013, which contributed to the socio-economic development in Guiyang City. The evaluation index of water resource subsystem fluctuated, and decreased slightly during the study years. The evaluation index of ecological environment subsystem increased significantly, while the evaluation index of socio-economic subsystem decreased dramatically. [Conclusion] The contribution of water resources subsystems to water resources carrying capacity has decreased. The improvement of ecological environment is the main driver of the increasing water resources carrying capacity, while the socio-economic subsystem is the main obstruction of water resources carrying capacity.