Reaserch On Simulation Of Urban Residential Land Expansion’s Micro Drive Mechanism Based On CA And Agent-based Model

China is now in the stage of rapid urbanization, and is faced with the contradiction between the rapid development and scale control, the contradiction btween supply and demand, the contradiction between resouces utilization and farmland protection. Reasearch on the drivers of urban expansion will help to achieve the optimal allocation of land resouces, to coordinate the relationship btween population, resources, environment and development, to be beneficial to the social stability and sustainable economic development.This paper used the combination of CA and ABM to explore the internal driving forces of urban residential land expansion in Hangzhou. Based on the datas of environment layer, the CA model used Logistic regression model to determine the transformation rule. The ABM included Resident Agent, Developer Agent and Government Agent. Resident Agent mainly considered the choosing effectiveness for living. Developer Agent mainly considered the maximization of the expected revenue, but also was affected by the behavior of Resident Agent. And Government Agent mainly considered its double demands of "government people" and "economic man"This paper established a model of urban residential land expansion based on CA and a model of urban residential land expansion based on CA-ABM, and choosed Hangzhou as the example to test models’s simulation accuracy. The results showed that the CA-ABM model simulation results were better than the CA model simulation results, and can simulate the dynamics changes in urban residential land expansion better.This paper set three different scenarios:resident-led, developer-led and government-led, to explore the microscopic driving mechanism of urban residential land expansion. And based on the simulation results analysis and driving forces analysis, this paper put forward some policy proposals for the urban residential land reasonale expansion:1. Introduce the system of public participation, develop the planning reasonably and carry out strict planning regulation;2. Strengthen the publicity and transparency of the real estate market’s information;3. Deepen the reform of tax system to reduce the local governments’"land finance" dependency;4. Reasonably guide the expansion of residential land in urban fringe locations and implement the urban planning strictly.