Abstract: The forest ecosystem is characterized by strong ecological functions, its protection and restoration functions are an important means of improving macro-ecological environment. With the rapid economic development and urbanization process,the urban area has been expanded,and a large number of woodlands,wetlands have been exploited for other purposes. This trend has resulted in the constant changes of spatial distribution of the urban landscape,and undoubtedly brought an important impact on the regional ecological security pattern and macro-ecological environment. The study of urban expansion's impact on the driving force of landscape ecological security patterns in Chengdu City has shown that the main driving force of the urban landscape ecological security pattern change comes from the urban expansion. An endless struggle has been going between ecological security pattern and urban expansion,and human disturbance generates deep impact on the landscape ecological security pattern. Land use changes,urban expansion,as well as the non-rural population growth affect the entire landscape ecological security pattern changes directly or indirectly.