Threats often have the characteristics of dynamic evolution with the development of bilateral confrontation. Traditional threat assessment methods are more based on static threats and lack of prediction of dynamic threats. To solve this problem， this paper proposes a threat assessment method for aerial targets under confrontational conditions. Setting the red side as the attacking side and the blueside as the defending side. The reinforcement learning model is established with the enemy target as the agent， and its state space， action space， transition function and reward function are designed. The threat assessment model is established， the threat element index is established， and the threat assessment method is designed. The model is trained， and the trained model can predict the enemy aerial target threat according to the confrontation situation. Through test and analysis， the method is more reasonable for threat assessment of enemy aerial targets under confrontation conditions.

With regard to the non-cooperative actively approaching spacecraft with maneuverability， a threat index calculation model to analyze the threat of the chaser to the target is proposed. We extract the impulse and the time required for rendezvous based on two impulses Lambert algorithm as threat elements after analyzing the mission mode of the chaser. The most threatening route is selected to weigh the impulse and time in order to calculate the comprehensive threat index. Simulation results show that the threat index of the chaser is very sensitive to the changes of orbital elements. Comparing the commonly used relative distance index， the threat index can identify the maneuver intention more quickly according to its trend. Under the complex space situation， the threat index analysis model is able to predict the threat of actively approaching spacecraft so as to take timely protective measures and improve the survivability of satellites.