The paper investigates the sustainability of regional system development on the basis of a special life cycle model. Three tendencies of regional system sustainability research are mentioned. The first tendency is based on descriptive characterization. The second tendency uses the theory of catastrophes. The third tendency includes the dependence of system functioning on the type of management. This paper gives a variant using life cycle based on the expenditure of resources of the region. In analyzing the sustainability and life cycle model, two models are considered: the Lotka Volterra model, the logistic model. The life cycle model is formed as a composite model of two parts. The first part reflects the phase of growth and stability. The second part of the model reflects the degradation of the system. It is shown that the basis of the life cycle is a resource. Resource depletion shortens the life cycle and makes the regional system unstable. The rate of resource expenditure can also make the regional system unstable. #COMESYSO1120.