Rapid urbanization may lead to fragmentation of ecological patches and decrease in the landscape connectivity of urban green spaces. This change may result in continuous deterioration of the ecological environment. A well-connected ecological network can effectively alleviate many ecological and environmental problems caused by rapid urbanization and is important for biodiversity protection, urban ecosystem restoration, and sustainable development of urban and rural ecological spaces. This study selected the Daxing District of Beijing City as the study area and identified ecological source patches using remotely sensed land cover data and the morphological spatial pattern analysis (MSPA) tool. The minimum cumulative resistance (MCR) model was used to generate a resistance surface, based upon which potentially ecological corridors were extracted. Then, gravity model was applied to classify the importance of the corridors. Finally, the ecological network was evaluated and optimized using the relevant network index, and the measures to optimize the ecological network were identified. The results indicated that forest land occupied the largest proportion (37.32%) of land cover in the study area, followed by construction land (28.9%) and farmland (19.2%). The MSPA analysis divided the ecological patches that were identified into seven types: core area, bridging area, ring road area, isolated island area, pore area, edge area, and branch area. The core area was 349.42km², accounting for 33.73% of the study area. The majority of ecological fragments were distributed in the west, south, and southeast of the Daxing District and along the Yongding River. According to the values of patch importance (dIIC and dPC), 16 key ecological sources were selected, covering area of 85.15km² and accounting for 8.2% of the study area. A resistance surface was generated by the MCR model and 120 corridors were identified. The importance of the corridors, which included 39 important corridors and 81 general corridors, was classified using the gravity model. In terms of ecological network optimization, 4 ecological sources, 70 planned ecological corridors, and 17 ecological nodes were added, and 20 "stepping stones" were planned for construction to restore 72 major ecological breakpoints. After implementing these optimization measures, the α index, β index, and γ index all increased, indicating that the connectivity of the whole ecological network had been optimized effectively. The study found that during the process of rapid urbanization in the Daxing District, the ecological problems such as fragmentation, uneven distribution, and poor connectivity had emerged. The study area had many green spaces, but they were concentrated on the edges of the study area. The ecological sources and corridors were mainly distributed in the west and southeast of the study area, and the central and northern regions lacked large-scale ecological sources and were not closely connected to the surrounding areas. In future ecological construction, to protect the existing ecological sources and corridors, we should strengthen the construction of additional ecological sources in the central and northern parts of the study area. We should also continue to improve the connectivity of the ecological network of the study area, which will help to restore the urban ecosystem and conserve biodiversity throughout the region. This study can provide reference for ecological construction, optimization restoration, and sustainable development of ecological space in other rapidly urbanized areas.