Based on case study of droughts in Southwest China，this paper intends to analyze the fundamental reasons behind the disasters，and review the cognitive problems of urbanization pattern，knowledge management system，water strategy and water system. The drastic water crisis now facing China calls for a knowledge convergence that could be preliminarily defined as urban ecology and includes a wide variety of different disciplines，such as geography，meteorology，urbanology，engineering，economics and political science，as well as new contents on informatized cities，post-modern cities，intelligent cities and science of urban disaster. In some cases，“soft” knowledge，such as religion，sociology and anthropology，would be needed to solve the urban ecological problems in China more effectively.