Context <p>Delimiting urban growth boundaries (UGBs) in oases is crucial for reducing the negative effects of urban expansion on fragile ecosystems and requires integrating ecological protection with different urban expansion modes. However, existing methods fail to combine these two elements.</p> Objectives <p>This study aims to develop a new approach for delimiting UGBs in oases by incorporating the protection of ecosystem services and modes of urban expansion.</p> Methods <p>We first established a scenario matrix by combining these two elements and coupled a patch-based urban expansion model and an ecosystem service assessment model to delimit UGBs under different scenarios. Then, we evaluated the effectiveness of the new approach by taking the Ganzhou District of Zhangye city as an example.</p> Results <p>We found significant differences in the protection effects of ecosystem services across urban expansion models, i.e., spontaneous growth is the most effective at protecting food production, while a balance of organic and spontaneous growth is the most effective at protecting habitat quality and carbon sequestration. Under the optimal scenario of UGBs, future habitat quality, carbon sequestration, and food production will decline by only 3.2%, 1.4%, and 0.9%, respectively.</p> Conclusions <p>This study presents an effective method for delimiting UGBs for oases, with the aim of minimizing the ecological influences of urban expansion.</p>