Abstract: In order to understand the status quo and changeable tendency of ecological security in county area, the author took the example of Ningwu County, the headstream of Fenhe River, confronting serious eco-environment problem and considerable human impacts. Taking Ningwu as the study area and using variation coefficient method to determine the weights of the indices, the author built ecological security pattern based on Pressure-State-Response Model of organization for economic cooperation and development. The ecological security status was evaluated by calculating eco-security index with socio-economic statistical data of Ningwu in the recent 10 years. The results showed that: the situation of eco-security had been improved from heavy alarm to relative safety during 2001-2010. It reflected that the ecological economic system in Ningwu County in which a sharp conflict between its ecological environment and its social and economic growth tends to be relaxed constantly. The ecological safety awareness was growing, however, by force of the objective requirements of population growth and economic development, the situation of ecological security was still unstable.