Maximum flux principle and simulation on urban sustainable development

City is a complex, evolutionary and organic whole. The sustainable development problems of organic urban systems cannot be resolved just using modern science grounded upon reductionism, in which city seems to have to be gradually divided into many mechanical world reality as particles in physics or compound in chemistry. The new information reality for world is proposed in this paper, by which a universal ζ field dynamical equation is derived by maximum flux principle and new numerical method on sustainable development of organic urban system is then established, which can not only provide a new unified paradigm for urban systems, but also be instructive in rigorous practical evaluation, planning, regulation and control on urban engineering.