It is important to study the change of urban water consumption structure and its driving force, which is of great significance to the sustainable development of water resources in the city, and the rational allocation of water resources. Based on the water quantity data of water resources of Nanchang city during 2005-2014, by using information entropy and equilibrium degree analysis method, the evolution law of water consumption structure and the driving force factor of water structure in Nanchang city was analyzed by SPSS. The results indicated that agricultural water consumption is the greatest in the whole water consumption structure, followed by industrial and domestic water consumption, and the ecological water consumption is the smallest; overall information entropy and equilibrium degree of water utilization structure showed upward trend. The factor analysis results showed that the social-economic factor is the principal driving force of water utilization structure evolution.