With the well-developed theory and methodology of landscape security pattern, and by the analysis of natural, biological, and cultural processes, it's possible to judge and plan the landscape security pattern of definite ecological process, i. e., to maintain the minimum ecological land use of this ecological process both in pattern and in area, which is of strategic significance. From the aspects of land coverage and spatial quality, this paper defined the ecological land use as the ecosystem (land unit) and its spatial position that have important significance in safeguarding critical ecological processes and providing critical ecosystem services. Taking three towns in eastern Beijing as an example, the ecological land use based on storm water management and biological conservation was analyzed. In the study area, the ecological land use at low, medium, and high security levels occupied 20.4%, 31.1%, and 48.6% of the total, respectively, indicating that the landscape security pattern approach based on critical ecological processes was an effective tool in the quantitative study of ecological land use, having important reference value for urban and land planning.