Abstract: Because of various urban crises, the endogenesis of secondary & tertiary industries has been challenged. Therefore, urban agriculture was oriented as the balancer for secondary & tertiary industries to handle the “middlecausation risks”, and a model of endogenous growth was built. The method of optimal control was employed to obtain the longterm equilibrium economic growth rate, the transversality conditions, the relationship between the output flexibilities of input factors in the two subsystems, the relationship between the elasticity coefficients of intertemporal substitution in consumption, as well as the optimal conditions for the entire system. The results indicate that the combination of urban agriculture with secondary & tertiary industries to be a whole is a realistic way to turn urban crises endogenous; furthermore, the endogenous growth model built for urban agriculture in this paper extends the description space of original endogenous growth model, and it will shed light on the development of urban agriculture.