Abstract: Abstract: The most essential issue for the sustainable development of the peri-urban areas is how to optimize land use efficiency and coordinate spatial function of production, life and ecology. Land consolidation is one of the key solutions to address this issue. However, the study on the land consolidation is mainly limited to rural areas and focuses on farmland production, without considering the overall development and utilization of space. In order to fill the gaps, this study proposed a method to determine functional units for land consolidation (FULC) in peri-urban taking the overall development and utilization of space into consideration. The determination of FULC contained 4 steps. First, functional areas of land consolidation were decided by using the Delphi method and the figure layering method according to the regional development strategies. Second, the functional areas were divided into several evaluation units on the basis of internal homogeneity, implementation independence, evaluation operability and other principles. Third, the functional status of evaluation units was measured by regional commercial law and multi-index comprehensive evaluation method from 3 aspects, i.e. the spatial structure status, the spatial structure target and the space quality target, for 5 purposes, i.e. improving urban production, rural production, urban life, rural life, and ecology. Forth, cluster analysis of the consolidation function was performed to demarcate FULC by distance method and Delphi method. The dominant functions could be classified into 5 categories, i.e. fertile farmland consolidation, industrial land saving and intensive consolidation, rural residential environment consolidation, urban renewal consolidation and ecological comprehensive consolidation. Haidian District, Beijing, a typical peri-urban area, was used as a case to demonstrate this framework. Three functional areas for land consolidation were formed in Haidian District integrating multiple planning objectives, namely, the production-oriented ecological technical zone in the north, the ecology-oriented historical and cultural scenic spots in the middle, and the life-oriented Zhongguancun Science City in the south. In the areas, 93 evaluation units were chosen to evaluate in Step 2-4. Finally, 54 FULCs were determined, including a fertile farming consolidation unit, 28 rural residential environment consolidation units, 5 industrial land saving and intensive consolidation units, 17 urban renewal consolidation units and 3 ecological comprehensive consolidation units. As a result, the spatial optimization function of comprehensive land consolidation could be fully played through the demarcation of FULC. Therefore, spatial structure was optimized effectively, for instance, agricultural production space would be increased by 975 hm2, and 3 061 hm2 rural life space and 308 hm2 urban living space would be improved, in addition 617 hm2 collective industrial park would be upgraded. Furthermore, the quality of space development was guaranteed, for example, the quality level of farmland would be increased by 1.4 grades, the level of agricultural scale and industrialization would be increased by 3.7%, and the construction land area for unit GDP (gross domestic product) would be reduced by 8% annually. In conclusion, the analysis shows that the method can provide technical support and practical references for planners and executors to the differentiation design of land comprehensive consolidation based on functional orientation in peri-urban areas.