Abstract: The purpose of this study is to explore the UGB delimiting method, which can address concerns on both policy planning and the pattern of natural development. Taking Yubei district of Chongqing as the case study area, the study is based on the data of land-use, social economy and multiple spatial planning, and the urban land demands in three different industrial transformation speeds scenes are calculated by the method of “Marginal land-use”. Then based on the idea of “anti-planning”, the Multi-plan integration and FLUS model is introduced to explore the land-use distribution, and the rigid UGB, short-term and long-term flexible UGB in three industrial transformation scenes are delimited. The result shows that：1) Artificial initial land-use, which combines Multi-plan integration and land-use status, make the UGB delimiting result adapt to the demand of development planning. 2) Industrial transformation slows down the urban-land expansion in Towns of Xinglong, Gulu and Shichuan, and the long-term flexible UGB delimitation result shows a moderate diminish. 3) The rigid UGB in Yubei district distributes along the three mountains, and the area of remaining land that can be developed beyond the rigid UGB is 59 52072 hm². The areas of short-term and long-term flexible UGB in three scenes are 35 781780, 48 34361, 44 73133 and 41 061.13 hm², respectively. The remaining land neither in rigid UGB nor in flexible UGB mainly distribute in towns of Luoqi, Gulu and the airport area in Shuangfengqiao Street. The methods used in this study take the rigid and flexible concept of UGB into consideration and combines the Top-down politic factors and Down-top natural pattern factors effectually. The UGB delimiting results would make it effective to achieve ecological security and urban smart growth.