With the increase of the urban population and the rapid development of urbanization in China, a large number of old buildings will be demolished and produce a huge amount of waste. Currently the recycling ratio of old building materials is very low, which results in the problems of resource waste and environment pollution. This greatly challenges urban sustainable development. With respect to the continual growth of demolition waste quantities, it is urgent to research how to implement effective management of demolition wastes by focusing on the demolition agents’ behavior. Based on the theory of complexity, this paper analyzes the demolition waste management from the perspective of complex adaptive system. Taking into account the “green” demolition (building dismantling) and conventional demolition (building demolished) methods, the agent-based modeling method with Repast Simphony platform is applied to simulate interactions between demolition agents. The longitudinal trend of demolition waste quantities is forecasted.