This paper makes a comprehensive assessment of Guangzhou's urban sustainable development, and analyzes its utilization of natural resources and energy. The results are: since the reform and opening up, Guangzhou City is advancing towards sustainable development, but it is at the expense of environmental degradation to some extend. The expressing problem of Guangzhou is that urban ecological system is being destroyed, which are prominently presented by the waste of living water; the lower reuse-rate of industry water; the huge emission of industrial dusts; and the lower use-rate of materials. Enterprises are the basic unit of urban economy, and their consciousness and behaviors of environmental protection are critical to urban sustainable development. According to questionnaires, the aim of Guangzhou's enterprises has transferred to profit maximization, but their consciousness of environmental protection is too weak. As to their behaviors of environmental protection, Guangzhou's enterprises are somewhat passive: their driving forces of investment on environmental protection are from Environmental Protection Law, the citizens' suing, and the government regulations; their investment on environmental protection is too low; their environmental protection organ plays a less important role; they dispose pollution at the end stage of production.