In order to accurately describe the security capability of the air transportation system， the concept of resilience is introduced to evaluate its risk resistance and recovery level. First， a hierarchical Bayesian network model is established， and the factors that affect the normal operation of the air transportation system are analyzed. Second， the system resilience is evaluated， and the resilience and changing trends of China's air transportation system from 2010 to 2019 are quantitatively analyzed. Third， the impact of factors on the overall resilience level is analyzed， and the change of the underlying nodes during the COVID-19 epidemic is taken as an example. Then， the overall resilience level of the system is evaluated through adjusting each node of the model. The research results show that the overall resilience evaluation value of the air transportation system is between 54% and 60.2%， and it exhibits a fluctuating upward trend with the continuous social and economic development. Under the influence of the COVID-19 epidemic， the service level of the system has been greatly affected， but the overall system can still maintain a certain degree of resilience. The Bayesian network model can better quantify the resilience of the air transportation system， and help improve the resilience of the system. This method provides effective control strategies and theoretical methods for the sustainable development and resistance to shocks of the air transportation industry.