[Objective] A scientific and reasonable ecological security pattern was constructed in order to provide a reference for the coordinated promotion of sustainable development of regional land and space through ecological civilization construction.[Methods] Based on biodiversity, water resource security, and geological hazard avoidance, the importance of ecological land in Nanjing City of Jiangsu Province was quantitatively evaluated to identify ecological resources. A modified ecological resistance surface was constructed by considering the influence of PM_2.5 and nighttime light on species migration. A regional ecological security pattern was built by the minimum cumulative resistance model.[Results] The ecological resources of the 490.3 km² ecological land were identified, and the national and provincial nature reserves of Nanjing City were located within the ecological area. The identification results were reasonable. The revised resistance range of the ecological resistance surface was 0-43 854.6. The high-resistance area was located on the south bank of the Yangtze River, such as the Gulou, Qinhuai, and Eastern Jianye Districts. The low-resistance area was located in the center of Pukou, Xuanwu, and the northeast of Jiangning District. The revised resistance could characterize the differences of the regional ecological processes accurately. Relying on the core components of the ecological resource areas, buffer zones, and ecological corridors, the ecological security pattern framework ("one belt, three zones, and multiple axes") of Nanjing was established.[Conclusion] The improved method of constructing an ecological security pattern was effective, and the established ecological security pattern framework is consistent with the existing main function zone implementation plan of Nanjing City.