In order to improve the ecological environment of Beijing, the municipal government proposed a project to build one million mu of forest in the next five years. Under the conditions of limited land and serious conflicts among agriculture, urban construction, and ecological conservation, where and how to afforest in order to bring role of large scale afforestation into full play becomes the key issue. This paper points out the shortcomings of the conventional strategies of afforestation and greening, mainly the green buffer, in Beijing, by proving that it is ineffective in improving the ecological situation. And then it presents three types of large scale afforestation based on ecological security pattern that aiming at achieving comprehensive ecosystems services: the overall ecological corridors based on the regional ecological security pattern in the plain area of Beijing, the greenway network that focuses on fulfilling the recreational need of the residents and tourists, and the agroforestry network that integrates agricultural production and potential urban expansion of the future. According to the characteristics of land use, combined with above three models, it will
be implemented in the small plain area of Beijing in the form of land patches, thus realizing the ecological infrastructure with integrated ecosystem services such as production, regulation, biodiversity
conservation, as well as culture and recreation.