In recent years, resilient cities have become an important topic in urban development. The global COVID-19 pandemic has raised widespread concerns regarding the prevention and control of public safety incidents. In the post-pandemic era, enhancing cities’ capacity to withstand and recover from large-scale public safety events has become an urgent issue. This study concentrates on 35 prefecture-level cities in Northeast China and constructs an indicator system based on five dimensions: social security, economic development, urban environment, intelligence, and resilience. By combining the theory of Complex Adaptive Systems (CAS) with urban resilience, and utilizing techniques such as geographic detectors and the NK model, the study provides strategies for enhancing urban resilience. The study identifies socio-economic factors, social security, and the built environment as the core influences on urban resilience in Northeast China. Socio-economic factors account for the largest contribution, at 58.7%, followed by social security at 16.6%, and the built environment at 10.2%. Although the overall resilience level in the region is relatively high, adaptability remains low: 0% of cities are classified as “Adaptation,” 77.1% as “Local Adaptation,” and 22.9% as “Non-adaptation.” These findings indicate that the high resilience levels are primarily attributable to historically low socio-economic development, which has minimized the relative impact of pandemic shocks. The study categorizes cities based on their adaptive capacity into three types: economic priority, livelihood security, and planning and construction, and proposes corresponding strategies for improving resilience for each type of city.